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Bukanova JV, Solntseva EI, Skrebitsky VG. Factors promoting the release of picrotoxin from the trap in the GABA(A) receptor pore. Neurochem Int 2024; 175:105703. [PMID: 38395151 DOI: 10.1016/j.neuint.2024.105703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/31/2024] [Accepted: 02/21/2024] [Indexed: 02/25/2024]
Abstract
Picrotoxin (PTX), a convulsant of plant origin, has been used in many studies as research tool. PTX is the open channel blocker of the GABAA receptor (GABAAR). Being in the pore, PTX initiates transfer of the channel to the closed state and thus it falls into the "trap". The consequence of this PTX trapping is so-called aftereffect, i.e. continuation of the blockade of the GABA-induced chloride current (IGABA) after removal of PTX from the external solution. The present work shows that the positive allosteric modulators (PAMs) of the GABAA receptor, allopregnanolone (Allo) and zolpidem (Zolp) as well as a high concentration of GABA shortened the PTX aftereffect. Experiments were carried out on isolated Purkinje neurons of the rat cerebellum using the whole-cell patch-clamp method. IGABA was induced by applications of 5 μM GABA (EC30) for 1 s with 30 s intervals. 50 μM PTX completely blocked IGABA, and recovery upon PTX washout occurred with a time constant (τrec) of 20.2 min. 1 μM Allo reduced the blocking effect of PTX by 30% and accelerated the recovery of IGABA by almost 10 times (τrec = 2.4 min). 0.5 μM Zolp did not change the IGABA block in the presence of PTX but accelerated the recovery of IGABA by more than 3 times (τrec = 5.6 min). Increasing the GABA concentration to 20 μM did not change the blocking effect of PTX, but accelerated recovery by 6 times (τrec = 3.3 min). The mechanism of the shortening of the PTX aftereffect is presumably the expansion of the GABAAR pore in the presence of PAMs and a high concentration of the agonist and, as a consequence, the escape of PTX from the "trap". The work describes new pharmacological properties of Allo and Zolp.
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Affiliation(s)
- Julia V Bukanova
- Brain Research Institute, Research Center of Neurology, Moscow, Russia
| | - Elena I Solntseva
- Brain Research Institute, Research Center of Neurology, Moscow, Russia.
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Ghashghayi E, Zendehdel M, Khodadadi M, Rahmani B. Central dopaminergic, serotoninergic, as well as GABAergic systems mediate NMU-induced hypophagia in newborn chicken. Int J Neurosci 2024; 134:353-363. [PMID: 35901030 DOI: 10.1080/00207454.2022.2102980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/29/2022] [Accepted: 06/23/2022] [Indexed: 10/16/2022]
Abstract
AIM Dopaminergic, serotoninergic, and GABAergic systems influence feeding; however, it is unknown how these chemicals interact with neuromedin U (NMU)-induced feeding in birds. In the current study, ten trials were conducted to determine the links between the above-mentioned systems and NMU. MATERIALS AND METHODS In the foremost experimentation, chickens were given intracerebroventricularly injections of NMU (0.1, 1, and 10 µg). NMU (10 µg), SCH23390 (5 nmol), a D1 receptor antagonist, and NMU + SCH23390 were administered in the second experiment. In subsequent experiments, instead of SCH23390, were applied AMI-193 (5 nmol D2 receptor antagonist), NGB2904 (6.4 nmol D3 receptor antagonist), L-741,742 (6 nmol D4 receptor antagonist), 6-OHDA (2.5 nmol dopamine inhibitor), SB242084 (5-HT2c receptor antagonist, 1.5 μg), 8-OH-DPAT (5-HT1A receptor agonist, 15.25 nmol), picrotoxin (GABAA receptor antagonist, 0.5 μg), and CGP54626 (GABAB receptor antagonist, 20 ng). Then, cumulative intake of food was recorded for 2 h. RESULTS According to the results, NMU reduced feeding when compared to the control group (p < 0.05). The NMU-induced hypophagia was reduced with co-injection of NMU and SCH23390 (p < 0.05). Hypophagia was diminished with NMU and AMI-193 (p < 0.05). NMU + NGB2904 and NMU + L-741,742 co-injections had no influence (p > 0.05). 6-OHDA reduced the hypophagia (p < 0.05). NMU and SB242084 decreased the hypophagia (p < 0.05), whereas NMU and 8-OH-DPAT had no effect (p > 0.05). The effects were amplified with picrotoxin (p < 0.05). NMU with CGP54626 had no influence on the hypophagia (p > 0.05). CONCLUSION Thus, NMU-induced hypophagia is probably mediated by D1/D2, 5-HT2c, and GABAA receptors in neonatal chicks.
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Affiliation(s)
- Elham Ghashghayi
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Morteza Zendehdel
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Mina Khodadadi
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Behrouz Rahmani
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
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Johnson SM, Gumnit MG, Johnson SM, Baker TL, Watters JJ. Disinhibition does not play a role in endomorphin-2-induced changes in inspiratory motoneuron output produced by in vitro neonatal rat preparations. Respir Physiol Neurobiol 2024; 320:104186. [PMID: 37944625 PMCID: PMC10843717 DOI: 10.1016/j.resp.2023.104186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/23/2023] [Accepted: 11/04/2023] [Indexed: 11/12/2023]
Abstract
Low level activation of mu-opioid receptors (MORs) in neonatal rat brainstem-spinal cord preparations increases inspiratory burst amplitude recorded on cervical spinal roots. We tested whether: (1) MOR activation with an endogenous ligand, such as endomorphin-2, increases inspiratory burst amplitude, (2) disinhibition of GABAergic or glycinergic inhibitory synaptic transmission is involved, and (3) inflammation alters endomorphin-2 effects. Using neonatal rat (P0-P3) brainstem-spinal cord preparations, bath-applied endomorphin-2 (10-200 nM) increased inspiratory burst amplitude and decreased burst frequency. Blockade of GABAA receptors (picrotoxin), glycine receptors (strychnine), or both (picrotoxin and strychnine) did not abolish endomorphin-2-induced effects. In preparations isolated from neonatal rats injected 3 h previously with lipopolysaccharide (LPS, 0.1 mg/kg), endomorphin-2 continued to decrease burst frequency but abolished the burst amplitude increase. Collectively, these data indicate that disinhibition of inhibitory synaptic transmission is unlikely to play a role in endomorphin-2-induced changes in inspiratory motor output, and that different mechanisms underlie the endomorphin-2-induced increases in inspiratory burst amplitude and decreases in burst frequency.
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Affiliation(s)
- Stephen M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
| | - Maia G Gumnit
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Sarah M Johnson
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Tracy L Baker
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Jyoti J Watters
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
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Vosoughi A, Zendehdel M, Hassanpour S. Central effects of the serotoninergic, GABAergic, and cholecystokinin systems on neuropeptide VF (NPVF)-induced hypophagia and feeding behavior in neonatal broiler chicken. Neurosci Lett 2024; 818:137557. [PMID: 37972685 DOI: 10.1016/j.neulet.2023.137557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023]
Abstract
The study was performed to evaluate the role of central serotoninergic, GABAergic, and cholecystokinin systems in neuropeptide VF (NPVF)-induced hypophagia in broiler chickens. In this study, 9 experiments were designed, each with one control and three treatment groups (n = 44 in each experiment). Control chicks of all groups were subjected to normal saline + Evans blue 0.1 % Intracerebroventricular (ICV) injection. In the first experiment, 3 groups of chicks received NPVF (4, 8, and 16 nmol). In experiment 2-9, one group of chicks received NPVF (16 nmol), another received 10 µg fluoxetine (serotonin reuptake inhibitor) (experiment 2), 1.25 µg PCPA (serotonin synthesis inhibitor) (experiment 3), 1.5 µg SB-242,084 (5-HT2C receptor antagonist) (experiment 4), 15.25 nmol 8-OH-DPAT (5-HT1A receptor antagonist) (experiment 5), 0.5 µg picrotoxin (GABAA receptor antagonist) (experiment 6), 20 ng CGP54626 (GABAB receptor antagonist) (experiment 7), 1 nmol devazepide (CCKA receptor antagonist) (experiment 8), and 1 nmol/L-365(-|-),260 (CCKB receptor antagonist) (experiment 9), and another final group received combination of specific neurotransmitter + NPVF Then, the cumulative food intake was measured until 120 min post-injection. ICV injection of NPVF (8 and 16 nmol) significantly decreased food intake (P < 0.05). Simultaneous injection of fluoxetine + NPVF and also picrotoxin + NPVF significantly increased hypophagia caused by NPVF (P < 0.05). However, co-administration of PCPA + NPVF and also SB242084 + NPVF significantly decreased NPVF-induced hypophagia (P < 0.05). Finally, 8-OH-DPAT, CGP54626, devazepide, and L-365,260 had no effect on the hypophagia brought on by NPVF (P > 0.05). Count-type behaviors were dose-dependent and decreased in groups that received NPVF compared to the control group (P < 0.05). Our finding recommended an interconnection between central NPVF and serotoninergic, GABAergic, and cholecystokinin systems in neonatal chickens.
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Affiliation(s)
- Anahita Vosoughi
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, 14155-6453 Tehran, Iran
| | - Morteza Zendehdel
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, 14155-6453 Tehran, Iran.
| | - Shahin Hassanpour
- Department of Basic Sciences, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
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Tong G, Griffin S, Sader A, Crowell AB, Beavers K, Watson J, Buchan Z, Chen S, Shenvi RA. C5 methylation confers accessibility, stability and selectivity to picrotoxinin. Nat Commun 2023; 14:8308. [PMID: 38097583 PMCID: PMC10721898 DOI: 10.1038/s41467-023-44030-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023] Open
Abstract
Minor changes to complex structures can exert major influences on synthesis strategy and functional properties. Here we explore two parallel series of picrotoxinin (PXN, 1) analogs and identify leads with selectivity between mammalian and insect ion channels. These are the first SAR studies of PXN despite its >100-year history and are made possible by advances in total synthesis. We observe a remarkable stabilizing effect of a C5 methyl, which completely blocks C15 alcoholysis via destabilization of an intermediate twist-boat conformer; suppression of this secondary hydrolysis pathway increases half-life in plasma. C5 methylation also decreases potency against vertebrate ion channels (γ-Aminobutyric acid type A (GABAA) receptors) but maintains or increases antagonism of homologous invertebrate GABA-gated chloride channels (resistance to dieldrin (RDL) receptors). Optimal 5MePXN analogs appear to change the PXN binding pose within GABAARs by disruption of a hydrogen bond network. These discoveries were made possible by the lower synthetic burden of 5MePXN (2) and were illuminated by the parallel analog series, which allowed characterization of the role of the synthetically simplifying C5 methyl in channel selectivity. These are the first SAR studies to identify changes to PXN that increase the GABAA-RDL selectivity index.
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Affiliation(s)
- Guanghu Tong
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Samantha Griffin
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Avery Sader
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Anna B Crowell
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland Street, Oberlin, Ohio, 44074, USA
| | - Ken Beavers
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Jerry Watson
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Zachary Buchan
- Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana, 46268, USA
| | - Shuming Chen
- Department of Chemistry and Biochemistry, Oberlin College, 119 Woodland Street, Oberlin, Ohio, 44074, USA.
| | - Ryan A Shenvi
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA.
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Cowgill J, Fan C, Haloi N, Tobiasson V, Zhuang Y, Howard RJ, Lindahl E. Structure and dynamics of differential ligand binding in the human ρ-type GABA A receptor. Neuron 2023; 111:3450-3464.e5. [PMID: 37659407 DOI: 10.1016/j.neuron.2023.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 09/04/2023]
Abstract
The neurotransmitter γ-aminobutyric acid (GABA) drives critical inhibitory processes in and beyond the nervous system, partly via ionotropic type-A receptors (GABAARs). Pharmacological properties of ρ-type GABAARs are particularly distinctive, yet the structural basis for their specialization remains unclear. Here, we present cryo-EM structures of a lipid-embedded human ρ1 GABAAR, including a partial intracellular domain, under apo, inhibited, and desensitized conditions. An apparent resting state, determined first in the absence of modulators, was recapitulated with the specific inhibitor (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid and blocker picrotoxin and provided a rationale for bicuculline insensitivity. Comparative structures, mutant recordings, and molecular simulations with and without GABA further explained the sensitized but slower activation of ρ1 relative to canonical subtypes. Combining GABA with picrotoxin also captured an apparent uncoupled intermediate state. This work reveals structural mechanisms of gating and modulation with applications to ρ-specific pharmaceutical design and to our biophysical understanding of ligand-gated ion channels.
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Affiliation(s)
- John Cowgill
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Chen Fan
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Nandan Haloi
- Department of Applied Physics, SciLifeLab, KTH Royal Institute of Technology, 17121 Solna, Sweden
| | - Victor Tobiasson
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Yuxuan Zhuang
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden.
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, SciLifeLab, Stockholm University, 17121 Solna, Sweden; Department of Applied Physics, SciLifeLab, KTH Royal Institute of Technology, 17121 Solna, Sweden.
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Bao Z, Chen X, Li Y, Jiang W, Pan D, Ma L, Wu Y, Chen Y, Chen C, Wang L, Zhao S, Wang T, Lu WY, Ma C, Wang S. The hepatic GABAergic system promotes liver macrophage M2 polarization and mediates HBV replication in mice. Antiviral Res 2023; 217:105680. [PMID: 37494980 DOI: 10.1016/j.antiviral.2023.105680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 07/28/2023]
Abstract
Macrophages display functional phenotypic plasticity. Hepatitis B virus (HBV) infection induces polarizations of liver macrophages either to M1-like pro-inflammatory phenotype or to M2-like anti-inflammatory phenotype. Gamma-aminobutyric acid (GABA) signaling exists in various non-neuronal cells including hepatocytes and some immune cells. Here we report that macrophages express functional GABAergic signaling components and activation of type A GABA receptors (GABAARs) promotes M2-polarization thus advancing HBV replication. Notably, intraperitoneal injection of GABA or the GABAAR agonist muscimol increased HBV replication in HBV-carrier mice that were generated by hydrodynamical injection of adeno-associated virus/HBV1.2 plasmids (pAAV/HBV1.2). The GABA-augmented HBV replication in HBV-carrier mice was significantly reduced by the GABAAR inhibitor picrotoxin although picrotoxin had no significant effect on serum HBsAg levels in control HBV-carrier mice. Depletion of liver macrophages by liposomal clodronate treatment also significantly reduced the GABA-augmented HBV replication. Yet adoptive transfer of liver macrophages isolated from GABA-treated donor HBV-carrier mice into the liposomal clodronate-pretreated recipient HBV-carrier mice restored HBV replication. Moreover, GABA or muscimol treatment increased the expression of "M2" cytokines in macrophages, but had no direct effect on HBV replication in the HepG2.2.15 cells, HBV1.3-transfected Huh7, HepG2, or HepaRG cells, or HBV-infected Huh7-NTCP cells. Taken together, these results suggest that increasing GABA signaling in the liver promotes HBV replication in HBV-carrier mice by suppressing the immunity of liver macrophages, but not by increasing the susceptibility of hepatocytes to HBV infection. Our study shows that a previously unknown GABAergic system in liver macrophage has an essential role in HBV replication.
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Affiliation(s)
- Ziyou Bao
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Xiaotong Chen
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; Department of Immunology, School of Clinical and Basic Medical Sciences, Shandong First Medical University& Shandong Academy of Medical Sciences, Jinan, China
| | - Yan Li
- Translational Medical Research Centre, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Wenshan Jiang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Di Pan
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China; Department of Physiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Lushun Ma
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China; Department of Paediatric Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Yunxiao Wu
- Department of Physiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Yunling Chen
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China; Department of Physiology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Chaojia Chen
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Liyuan Wang
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Songbo Zhao
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Tixiao Wang
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Wei-Yang Lu
- Department of Physiology and Pharmacology, Robarts Research Institute, University of Western Ontario, Canada.
| | - Chunhong Ma
- Department of Immunology, Key Laboratory for Experimental Teratology of Ministry of Education, Shandong Provincial Key Laboratory of Infection & Immunology, School of Basic Medical Science, Shandong University, Jinan, China.
| | - Shuanglian Wang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China.
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Nimitvilai-Roberts S, Woodward JJ. The ethanol inhibition of basolateral amygdala neuron spiking is mediated by a γ-aminobutyric acid type A-mediated tonic current. Alcohol Clin Exp Res 2022; 46:1665-1676. [PMID: 35915568 PMCID: PMC9509443 DOI: 10.1111/acer.14918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/19/2022] [Accepted: 07/28/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND The basolateral nucleus of the amygdala (BLA) plays an important role in the development of fear and anxiety-related behaviors. The BLA receives inputs from all sensory stimuli. After processing those stimuli, BLA neurons signal neurons within the central amygdala and other brain regions, including the ventral and dorsal striatum and frontal cortex. Studies suggest that the BLA is involved in drug dependence and in the reinforcing actions of ethanol. For example, acute exposure to ethanol reduces anxiety, while withdrawal from chronic ethanol exposure alters BLA synaptic transmission, which increases anxiety, a common underlying cause of relapse. Exposure to and withdrawal from chronic alcohol also disrupts many brain areas that connect with the BLA. Despite these important findings, the acute actions of alcohol on the intrinsic excitability of BLA neurons have not been fully characterized. METHODS Brain slices containing the BLA were prepared from adult C57BL/6J male mice. Whole-cell and sharp electrode electrophysiological recordings were performed to characterize the effects of acute ethanol on BLA neuronal and astrocyte function, respectively. RESULTS Ethanol inhibited action potential (AP) firing of BLA neurons but had no effect on BLA astrocyte resting membrane potential. The ethanol-induced inhibition of firing was concentration-dependent (11 to 66 mM) and accompanied by a reduction in the input resistance and an increase in the rheobase of BLA neurons. The inhibitory effect of ethanol was suppressed by picrotoxin, which blocks both γ-aminobutyric acid type A (GABAA ) and glycine receptors, but not by the selective glycine receptor antagonist strychnine, which suggests an involvement of GABAA receptors. Ethanol did not affect spontaneous inhibitory postsynaptic currents suggesting that the inhibition of BLA neuronal excitability by ethanol was not due to an increase in GABAA -mediated synaptic transmission. However, acute ethanol enhanced the amplitude of the holding current of BLA neurons, an effect that was prevented by picrotoxin, which by itself reduced the holding current. CONCLUSIONS These results suggest that BLA neurons express a GABA-mediated tonic current that is enhanced by acute ethanol, which leads to reduced excitability of BLA neurons.
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Affiliation(s)
| | - John J. Woodward
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425
- Department of Psychiatry and Behavioral Sciences, Addiction Sciences Division, Medical University of South Carolina, Charleston, SC 29425
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Rohbeck E, Hasse B, Koopmans G, Romero A, Belgardt BF, Roden M, Eckel J, Romacho T. Positive allosteric γ-aminobutyric acid type A receptor modulation prevents lipotoxicity-induced injury in hepatocytes in vitro. Diabetes Obes Metab 2022; 24:1498-1508. [PMID: 35434888 DOI: 10.1111/dom.14719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 11/29/2022]
Abstract
AIM To determine if a novel positive allosteric modulator of the γ-aminobutyric acid type A (GABAA ) receptor, the thioacrylamide-derivative HK4, which does not penetrate the blood-brain barrier, protects human hepatocytes against lipotoxicity-induced injury. MATERIALS AND METHODS Allosteric modulation of the GABAA receptor by HK4 was determined by patch clamp in HEK-293 cells, calcium influx in INS-1E cells and by using the specific GABAA channel blockers picrotoxin and tert-butylbicyclophosphorothionate (TBPS) in HepG2 cells. Apoptosis was analysed using caspase 3/7, terminal deoxynucleotidyl transferase-dUTP nick end labelling (TUNEL) and array assays in HepG2 cells and/or human primary hepatocytes. Phosphorylation of STAT3 and the NF-κB subunit p65, protein disulphide isomerase (PDI) and poly-ADP-ribose polymerase-1 (PARP-1) was detected by Western blotting. RESULTS Patch clamping, calcium influx measurements and apoptosis assays with the non-competitive GABAA channel blockers picrotoxin and TBPS proved HK4 as a selective positive allosteric modulator of the GABAA receptor. In HepG2 cells, which expressed the main GABAA receptor subunits, HK4 prevented palmitate-induced apoptosis. This protective effect was mediated by downregulation of caspase 3/7 activity and was additionally verified by TUNEL assay. HK4 effectively prevented palmitate-induced apoptosis in human primary hepatocytes. HK4 reduced STAT3 and NF-κB phosphorylation, reduced cleaved PARP-1 expression and upregulated the endoplasmic reticulum (ER) chaperone PDI. CONCLUSIONS HK4 reduced lipotoxic-induced apoptosis by preventing inflammation, DNA damage and ER stress. We propose that the effect of HK4 is mediated by STAT3 and NF-κB. It is suggested that thioacrylamide compounds represent an innovative pharmacological tool to treat or prevent non-alcoholic steatohepatitis as first-in-class drugs.
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Affiliation(s)
- Elisabeth Rohbeck
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | | | | | - Alejandra Romero
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Bengt-Frederik Belgardt
- Institute for Vascular and Islet Cell Biology, German Diabetes Center at Heinrich Heine University, Leibniz Center for Diabetes Research, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Düsseldorf, München-Neuherberg, Germany
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- German Center for Diabetes Research (DZD), Partner Düsseldorf, München-Neuherberg, Germany
- Department of Endocrinology and Diabetology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Jürgen Eckel
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Tania Romacho
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
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Durakoglugil MS, Wasser CR, Wong CH, Pohlkamp T, Xian X, Lane-Donovan C, Fritschle K, Naestle L, Herz J. Reelin Regulates Neuronal Excitability through Striatal-Enriched Protein Tyrosine Phosphatase (STEP 61) and Calcium Permeable AMPARs in an NMDAR-Dependent Manner. J Neurosci 2021; 41:7340-7349. [PMID: 34290083 PMCID: PMC8412985 DOI: 10.1523/jneurosci.0388-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 06/13/2021] [Accepted: 07/08/2021] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease marked by the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles. Aβ oligomers cause synaptic dysfunction early in AD by enhancing long-term depression (LTD; a paradigm for forgetfulness) via metabotropic glutamate receptor (mGluR)-dependent regulation of striatal-enriched tyrosine phosphatase (STEP61). Reelin is a neuromodulator that signals through ApoE (apolipoprotein E) receptors to protect the synapse against Aβ toxicity (Durakoglugil et al., 2009) Reelin signaling is impaired by ApoE4, the most important genetic risk factor for AD, and Aβ-oligomers activate metabotropic glutamate receptors (Renner et al., 2010). We therefore asked whether Reelin might also affect mGluR-LTD. To this end, we induced chemical mGluR-LTD using DHPG (Dihydroxyphenylglycine), a selective mGluR5 agonist. We found that exogenous Reelin reduces the DHPG-induced increase in STEP61, prevents the dephosphorylation of GluA2, and concomitantly blocks mGluR-mediated LTD. By contrast, Reelin deficiency increased expression of Ca2+-permeable GluA2-lacking AMPA receptors along with higher STEP61 levels, resulting in occlusion of DHPG-induced LTD in hippocampal CA1 neurons. We propose a model in which Reelin modulates local protein synthesis as well as AMPA receptor subunit composition through modulation of mGluR-mediated signaling with implications for memory consolidation or neurodegeneration.SIGNIFICANCE STATEMENT Reelin is an important neuromodulator, which in the adult brain controls synaptic plasticity and protects against neurodegeneration. Amyloid-β has been shown to use mGluRs to induce synaptic depression through endocytosis of NMDA and AMPA receptors, a mechanism referred to as LTD, a paradigm of forgetfulness. Our results show that Reelin regulates the phosphatase STEP, which plays an important role in neurodegeneration, as well as the expression of calcium-permeable AMPA receptors, which play a role in memory formation. These data suggest that Reelin uses mGluR LTD pathways to regulate memory formation as well as neurodegeneration.
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Affiliation(s)
- Murat S Durakoglugil
- Department of Molecular Genetics
- Center for Translational Neurodegeneration Research
| | - Catherine R Wasser
- Department of Molecular Genetics
- Center for Translational Neurodegeneration Research
| | - Connie H Wong
- Department of Molecular Genetics
- Center for Translational Neurodegeneration Research
| | - Theresa Pohlkamp
- Department of Molecular Genetics
- Center for Translational Neurodegeneration Research
| | - Xunde Xian
- Institute of Cardiovascular Sciences and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Peking University, Beijing 100871, China
| | - Courtney Lane-Donovan
- Weill Institute for Neurosciences, University of California San Francisco, San Francisco, California 94158
| | | | - Lea Naestle
- Ludwig-Maximilians University of Munich, 80539, Munich, Germany
| | - Joachim Herz
- Department of Molecular Genetics
- Center for Translational Neurodegeneration Research
- Departments of Neuroscience and
- Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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11
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González-Trujano ME, Urbina-Trejo E, Santos-Valencia F, Villasana-Salazar B, Carmona-Aparicio L, Martínez-Vargas D. Pharmacological and toxicological effects of Ruta chalepensis L. on experimentally induced seizures and electroencephalographic spectral power in mice. J Ethnopharmacol 2021; 271:113866. [PMID: 33485978 DOI: 10.1016/j.jep.2021.113866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 12/22/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ruta chalepensis L. (Rutaceae) is used in traditional medicine to treat a wide variety of disorders such as rheumatism, fever, mental disorders, dropsy, neuralgia, menstrual problems, anxiety, and epilepsy. AIM OF THE STUDY To evaluate and compare the anticonvulsant properties of an aqueous extract and ethyl acetate (AcOEt) fraction of R. chalepensis on pentylenetetrazole (PTZ)-induced seizures and maximal electroshock (MES) test in mice, by analyzing behavior and electroencephalogram (EEG), as well as GABAA receptors involvement. METHODS The effect of an acute administration of different dosage of the aqueous extract (300 or 500 mg/kg) or AcOEt fraction (100, 300, 500 or 1000 mg/kg) of R. chalepensis was explored on two different models of acute seizure induction in mice, the PTZ and maximal electroshock (MES) tests. Behavioral and electrographic effects were quantified. Additionally, the possible involvement of the GABAA receptors was explored in the presence of picrotoxin (a non-competitive antagonist of the GABAA receptor). RESULTS AcOEt fraction of R. chalepensis was more efficient than aqueous extract to reduce the incidence of tonic-clonic seizures and mortality in a significant and dose-dependent manner in both the PTZ and MES tests. This anticonvulsant effect was not abolished in the presence of picrotoxin. The EEG spectral power analysis revealed that aqueous extract decreased alpha and beta power, while AcOEt fraction decreased alpha and gamma power confirming previous findings of its depressant effect in the central nervous system. It is important to mention that the highest dosage of the AcOEt (1000 mg/kg) produced a severe suppression or isoelectric EEG activity (EEG flattening), recognized as a comatose state, suggesting a neurotoxic effect at this dosage. CONCLUSION Our data reinforce that depressant and anticonvulsant effects of R. chalepensis depend in part on the presence of constituents from medium polarity. We also found that anticonvulsant effect is not mediated by GABAA receptors. In addition, cautious is emphasized when high doses of this natural product are used in traditional medicine since it might produce neurotoxic effects.
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Affiliation(s)
- M E González-Trujano
- Laboratorio de Neurofarmacología de Productos Naturales, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de La Fuente Muñiz", Calz. México-Xochimilco 101, Col. San Lorenzo Huipulco, 14370, Ciudad de México, Mexico.
| | - E Urbina-Trejo
- Laboratorio de Neurofisiología Del Control y La Regulación, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de La Fuente Muñiz", Calz. México-Xochimilco 101, Col. San Lorenzo Huipulco, 14370, Ciudad de México, Mexico.
| | - F Santos-Valencia
- Laboratorio de Neurofisiología Del Control y La Regulación, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de La Fuente Muñiz", Calz. México-Xochimilco 101, Col. San Lorenzo Huipulco, 14370, Ciudad de México, Mexico.
| | - B Villasana-Salazar
- Laboratorio de Neurofisiología Del Control y La Regulación, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de La Fuente Muñiz", Calz. México-Xochimilco 101, Col. San Lorenzo Huipulco, 14370, Ciudad de México, Mexico.
| | - L Carmona-Aparicio
- Laboratorio de Neurociencias, Instituto Nacional de Pediatría, 04530, Ciudad de México, Mexico.
| | - D Martínez-Vargas
- Laboratorio de Neurofisiología Del Control y La Regulación, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de La Fuente Muñiz", Calz. México-Xochimilco 101, Col. San Lorenzo Huipulco, 14370, Ciudad de México, Mexico.
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12
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Li F, Cui J, Shaheen T, Tang G, Wang T, Woolfley T, Li M. Biocidal efficacy of tutin and its influence on immune cells and expression of growth-blocking and neuroglian peptides in Mythimna separata (Lepidoptera: Noctuidae). Arch Insect Biochem Physiol 2021; 107:e21767. [PMID: 33835527 DOI: 10.1002/arch.21767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
Mythimna separata Walker (Lepidoptera: Noctuidae) is one of the major pests that can cause severe damage to grain crops. The development of low-toxicity and high-performance botanical insecticides is becoming the focus of new pesticide research to control M. separata. Tutin, a sesquiterpene lactone compound obtained from Coriaria sinica Maxim, a native Chinese poisonous plant, has antifeedant, absorption, and stomach poisoning against a variety of pests. To understand the toxic effect of tutin on M. separata larvae, we set out to determine their antifeedant, mortality, paralysis, weight change, and to examine the spreading of M. separata hemocytes under different concentrations of tutin treatment. Tissue distribution of the immune-associated gene growth-blocking peptide (GBP) and neuroglian peptide (Nrg) was detected by reverse transcription polymerase chain reaction (PCR). Furthermore, real-time quantitative PCR was carried out to determine the expression profiles of GBP and Nrg after different concentrations of tutin stimulation. Our results revealed that tutin exhibited significant antifeedant and insecticidal activities, paralysis, weight loss to M. separata. Besides, tutin significantly influenced on the morphology of hemocytes and enhanced the expression of GBP and Nrg in M. separata.
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Affiliation(s)
- Feifei Li
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Jun Cui
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Tayyab Shaheen
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Guanghui Tang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Tao Wang
- Nursing Department, College of Science and Engineering, Southern Arkansas University, Magnolia, Arkansas, USA
| | - Tracy Woolfley
- Nursing Department, College of Science and Engineering, Southern Arkansas University, Magnolia, Arkansas, USA
| | - Menglou Li
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
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13
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Voss LJ, Garcia V. Electrophysiological field potential identification of an intact GABAergic system in mouse cortical slices. Brain Res 2021; 1756:147295. [PMID: 33516817 DOI: 10.1016/j.brainres.2021.147295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 12/10/2020] [Accepted: 01/08/2021] [Indexed: 10/22/2022]
Abstract
In brain slice experiments there's currently no validated electrophysiological method for differentiating viability between GABAergic and glutamatergic cell populations. Here we investigated the neurophysiology of high frequency field potential activity - and its utility for probing the functional state of the GABAergic system in brain slices. Field potentials were recorded from mouse cortical slices exposed to 50 mM potassium ("elevated-K") and the induced high frequency (>20 Hz) response characterized pharmacologically. The elevated-K responses were also related to the high frequency activity imbedded in no-magnesium seizure-like events (SLE) from the same slices. The elevated-K response, comprising a transient burst of high frequency activity, was strongly GABAA-dependent. The size of the high frequency response was reduced by 71% (p = 0.001) by picrotoxin, but not significantly attenuated by either APV or CNQX. High frequency activity embedded in no-magnesium SLEs correlated with the elevated-K response. The success rate for generating an elevated-K response - and high frequency SLE activity - declined rapidly with increasing time since slicing. These findings support the hypothesis that in cortical slices, a functioning synaptic GABAergic system is evidenced by a strong high frequency component to no-magnesium SLE activity - and that the integrity of the GABAergic system degrades quicker than the excitatory glutamatergic system in this preparation.
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Affiliation(s)
- Logan J Voss
- Anaesthesia Department, Waikato District Health Board, Hamilton, New Zealand.
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14
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Abstract
Allopregnanolone, a positive modulator of GABAA receptors with antiseizure activity, has potential in the treatment of seizure emergencies. Instillation of allopregnanolone in 40% sulfobutylether-β-cyclodextrin into the nose in mice rapidly elevated the seizure threshold in the timed intravenous pentylenetetrazol (ED50, 5.6 mg/kg), picrotoxin (ED50, 5.9 mg/kg), and bicuculline seizure tests. The effect peaked at 15 min, decayed over 1 h, and was still evident in some experiments at 6 h. Intranasal allopregnanolone also delayed the onset of seizures in the maximal PTZ test. At an allopregnanolone dose (16 mg/kg) that conferred comparable effects on seizure threshold as the benzodiazepines midazolam and diazepam (both at doses of 1 mg/kg), allopregnanolone caused minimal sedation or motor toxicity in the horizontal screen test whereas both benzodiazepines produced marked behavioral impairment. In addition, intranasal allopregnanolone failed to cause loss-of-righting reflex in most animals, but when the same dose was administered intramuscularly, all animals became impaired. Intranasal allopregnanolone (10 mg/kg) caused a rapid increase in brain allopregnanolone with a Tmax of ~5 min after initiation of the intranasal delivery. High levels of allopregnanolone were recovered in the olfactory bulb (Cmax, 16,000 ng/mg) whereas much lower levels (Cmax, 670 ng/mg) were present in the remainder of the brain. We conclude that the unique ability of intranasal allopregnanolone to protect against seizures without inducing behavioral adverse effects is due in part to direct nose-to-brain delivery, with preferential transport to brain regions relevant to seizures. Benzodiazepines are commonly administered intranasally for acute seizure therapy, including for the treatment of acute repetitive seizures, but are not transported from nose-to-brain. Intranasal allopregnanolone acts with greater speed, has less propensity for adverse effects, and has the ability to overcome benzodiazepine refractoriness. This is the first study demonstrating rapid functional central nervous system activity of a nose-to-brain-delivered steroid. Intranasal delivery circumvents the poor oral bioavailability of allopregnanolone providing a route of administration permitting its evaluation as a treatment for diverse neuropsychiatric indications.
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Affiliation(s)
- Dorota Zolkowska
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA
| | - Chun-Yi Wu
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA
- Bioanalysis and Pharmacokinetics Core Facility, UC Davis Medical Center, Sacramento, CA, 95817, USA
| | - Michael A Rogawski
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
- Department of Pharmacology, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
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15
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Kim JJ, Gharpure A, Teng J, Zhuang Y, Howard RJ, Zhu S, Noviello CM, Walsh RM, Lindahl E, Hibbs RE. Shared structural mechanisms of general anaesthetics and benzodiazepines. Nature 2020; 585:303-308. [PMID: 32879488 PMCID: PMC7486282 DOI: 10.1038/s41586-020-2654-5] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/01/2020] [Indexed: 01/17/2023]
Abstract
Most general anaesthetics and classical benzodiazepine drugs act through positive modulation of γ-aminobutyric acid type A (GABAA) receptors to dampen neuronal activity in the brain1-5. However, direct structural information on the mechanisms of general anaesthetics at their physiological receptor sites is lacking. Here we present cryo-electron microscopy structures of GABAA receptors bound to intravenous anaesthetics, benzodiazepines and inhibitory modulators. These structures were solved in a lipidic environment and are complemented by electrophysiology and molecular dynamics simulations. Structures of GABAA receptors in complex with the anaesthetics phenobarbital, etomidate and propofol reveal both distinct and common transmembrane binding sites, which are shared in part by the benzodiazepine drug diazepam. Structures in which GABAA receptors are bound by benzodiazepine-site ligands identify an additional membrane binding site for diazepam and suggest an allosteric mechanism for anaesthetic reversal by flumazenil. This study provides a foundation for understanding how pharmacologically diverse and clinically essential drugs act through overlapping and distinct mechanisms to potentiate inhibitory signalling in the brain.
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Affiliation(s)
- Jeong Joo Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Anant Gharpure
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jinfeng Teng
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yuxuan Zhuang
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Rebecca J Howard
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Shaotong Zhu
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Colleen M Noviello
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Richard M Walsh
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Erik Lindahl
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
- Department of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, Solna, Sweden
| | - Ryan E Hibbs
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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16
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Yang S, Liu Y, Sun F, Zhang J, Jin Y, Li Y, Zhou J, Li Y, Zhu K. Gelsedine-type alkaloids: Discovery of natural neurotoxins presented in toxic honey. J Hazard Mater 2020; 381:120999. [PMID: 31430640 DOI: 10.1016/j.jhazmat.2019.120999] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 08/09/2019] [Accepted: 08/11/2019] [Indexed: 06/10/2023]
Abstract
The fascinating collection and evaluation of natural products with enormous structural and chemical diversity can contribute to ensure human health and inspire potential drug discovery. We reported the identification of 14-(R)-hydroxy-gelsenicine (HGE), a new component from poisonous honey, which has recently caused multiple serious intoxications and deaths up on consumption. The prevalence, toxicity, toxicokinetics and metabolic profile of HGE were evaluated through in vitro and in vivo analyses. HGE is a very toxic substance and shows significant gender difference with LD50 of 0.125 mg kg-1 and 0.295 mg kg-1 for the female and male mice, respectively. Toxicokinetics test indicates that HGE has good bioavailability in rats, and is metabolized extensively, in which hydroxylation, reduction, N-demethyl ether and glucuronication are the major metabolic pathways. Additionally, HGE shows specific neurotoxicity by enhancing the binding of γ-aminobutyric acid (GABA) to its receptors. We found that flumazenil, a selective antagonist of GABA receptor, could effectively increase the survival of the tested animals, which provides a potential therapy for future clinical applications.
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Affiliation(s)
- Shupeng Yang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Bee Products for Quality and Safety Control, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Bee Product Quality Supervision and Testing Center, Ministry of Agriculture, Beijing, 100093, PR China.
| | - Yuan Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, PR China
| | - Feifei Sun
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, PR China
| | - Jinzhen Zhang
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Bee Products for Quality and Safety Control, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Bee Product Quality Supervision and Testing Center, Ministry of Agriculture, Beijing, 100093, PR China
| | - Yue Jin
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Bee Products for Quality and Safety Control, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Bee Product Quality Supervision and Testing Center, Ministry of Agriculture, Beijing, 100093, PR China
| | - Yanshen Li
- College of Life Science, Yantai University, Yantai, Shandong, 264005, PR China
| | - Jinhui Zhou
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Bee Products for Quality and Safety Control, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Bee Product Quality Supervision and Testing Center, Ministry of Agriculture, Beijing, 100093, PR China.
| | - Yi Li
- Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Bee Products for Quality and Safety Control, Laboratory of Risk Assessment for Quality and Safety of Bee Products, Bee Product Quality Supervision and Testing Center, Ministry of Agriculture, Beijing, 100093, PR China.
| | - Kui Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, PR China.
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17
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Fujitani T, Matsuura T, Kawasaki M, Suzuki H, Nishimura H, Baba K, Yamanaka Y, Ohnishi H, Ueta Y, Sakai A. Presynaptic glutamatergic transmission and feedback system of oxytocinergic neurons in the hypothalamus of a rat model of adjuvant arthritis. Mol Pain 2020; 16:1744806920943334. [PMID: 32686583 PMCID: PMC7372626 DOI: 10.1177/1744806920943334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 05/31/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
The neurohypophysial hormone oxytocin (OXT) is synthesized in the hypothalamic paraventricular and supraoptic nuclei. Recently, some studies have considered OXT to be important in sensory modulation and that the OXT protein is upregulated by acute and chronic nociception. However, the mechanism by which OXT is upregulated in neurons is unknown. In this study, we examined the resting membrane potentials and excitatory postsynaptic currents in OXT-ergic neurons in the paraventricular nucleus in adjuvant arthritis rat model, a model of chronic inflammation, using whole-cell patch-clamping. Transgenic rats expressing OXT and monomeric red fluorescent protein 1 (mRFP1) fusion protein to visualize the OXT-ergic neurons were used, and the OXT-mRFP1 transgenic rat model of adjuvant arthritis was developed by injection of heat-killed Mycobacterium butyricum. Furthermore, the feedback system of synthesized OXT was also examined using the OXT receptor antagonist L-368,899. We found that the resting membrane potentials and frequency of miniature excitatory postsynaptic currents and spontaneous excitatory postsynaptic currents in OXT-monomeric red fluorescent protein 1 neurons in the paraventricular nucleus were significantly increased in adjuvant arthritis rats. Furthermore, L-368,899 dose-dependently increased the frequency of miniature excitatory postsynaptic currents and spontaneous excitatory postsynaptic currents in OXT-ergic neurons. Following bath application of the GABAA receptor antagonist picrotoxin and the cannabinoid receptor 1 antagonist AM 251, L-368,899 still increased the frequency of miniature excitatory postsynaptic currents. However, following bath application of the nitric oxide synthase inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride, L-368,899 did not alter the miniature excitatory postsynaptic current frequency. Thus, it is suggested that OXT-ergic neuron activity is upregulated via an increase in glutamate release, and that the upregulated OXT neurons have a feedback system with released endogenous OXT. It is possible that nitric oxide, but not GABA, may contribute to the feedback system of OXT neurons in chronic inflammation.
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Affiliation(s)
- Teruaki Fujitani
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Takanori Matsuura
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
- Department of Physiology, School of Medicine, University of
Occupational and Environmental Health, Kitakyushu, Japan
| | - Makoto Kawasaki
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Hitoshi Suzuki
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Haruki Nishimura
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kazuhiko Baba
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yoshiaki Yamanaka
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Hideo Ohnishi
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of
Occupational and Environmental Health, Kitakyushu, Japan
| | - Akinori Sakai
- Department of Orthopaedic Surgery, School of Medicine,
University of Occupational and Environmental Health, Kitakyushu, Japan
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Luft JG, Steffens L, Morás AM, da Rosa MS, Leipnitz G, Regner GG, Pflüger PF, Gonçalves D, Moura DJ, Pereira P. Rosmarinic acid improves oxidative stress parameters and mitochondrial respiratory chain activity following 4-aminopyridine and picrotoxin-induced seizure in mice. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1347-1358. [PMID: 31201429 DOI: 10.1007/s00210-019-01675-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/07/2019] [Indexed: 12/22/2022]
Abstract
Studies have indicated that epilepsy, an important neurological disease, can generate oxidative stress and mitochondrial dysfunction, among other damages to the brain. In this context, the use of antioxidant compounds could provide neuroprotection and help to reduce the damage caused by epileptic seizures and thereby the use of anticonvulsant drugs. Rosmarinic acid (RA) is an ester of caffeic acid and 3,4-dihydroxyphenylactic acid that prevents cell damage caused by free radicals, acting as an antioxidant. It also presents anti-inflammatory, antimutagenic, and antiapoptotic properties. In this work, we used two models of acute seizure, 4-aminopyridine (4-AP) and picrotoxin (PTX)-induced seizures in mice, to investigate the anticonvulsant, antioxidant, and neuroprotective profile of RA. Diazepam and valproic acid, antiepileptic drugs already used in the treatment of epilepsy, were used as positive controls. Although RA could not prevent seizures in the models used in this study, neither enhance the latency time to first seizure at the tested doses, it exhibited an antioxidant and neuroprotective effect. RA (8 and 16 mg/kg) decreased reactive oxygen species production, superoxide dismutase activity, and DNA damage, measured in hippocampus, after seizures induced by PTX and 4-AP. Catalase activity was decreased by RA only after seizures induced by 4-AP. The activity of the mitochondrial complex II was increased by RA in hippocampus samples after both seizure models. The results obtained in this study suggest that RA is able to reduce cell damage generated by the 4-AP and PTX seizures and therefore could represent a potential candidate in reducing pathophysiological processes involved in epilepsy.
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Affiliation(s)
- Jordana Griebler Luft
- Neuropharmacology and Preclinical Toxicology Laboratory, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90050-170, Brazil
| | - Luiza Steffens
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Sarmento Leite st., Porto Alegre, RS, 245, Brazil
| | - Ana Moira Morás
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Sarmento Leite st., Porto Alegre, RS, 245, Brazil
| | - Mateus Strucker da Rosa
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
- Programa de Pós-Graduação em Fisiologia, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-190, Brazil
| | - Gabriela Gregory Regner
- Neuropharmacology and Preclinical Toxicology Laboratory, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90050-170, Brazil
| | - Pricila Fernandes Pflüger
- Neuropharmacology and Preclinical Toxicology Laboratory, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90050-170, Brazil
| | - Débora Gonçalves
- Neuropharmacology and Preclinical Toxicology Laboratory, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90050-170, Brazil
| | - Dinara Jaqueline Moura
- Laboratory of Genetic Toxicology, Federal University of Health Sciences of Porto Alegre (UFCSPA), Sarmento Leite st., Porto Alegre, RS, 245, Brazil
| | - Patrícia Pereira
- Neuropharmacology and Preclinical Toxicology Laboratory, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90050-170, Brazil.
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19
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Zhu X, Yao Y, Li X, Dong J, Zhang A. Alteration of GABAergic signaling is associated with anxiety-like behavior in temporal lobe epilepsy mice. Prog Neuropsychopharmacol Biol Psychiatry 2019; 93:141-148. [PMID: 30951784 DOI: 10.1016/j.pnpbp.2019.03.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 03/20/2019] [Accepted: 03/29/2019] [Indexed: 12/18/2022]
Abstract
Temporal lobe epilepsy (TLE), which is one of the most common neurological diseases, is accompanied by a high incidence of psychiatric disorders. Among these psychiatric disorders, anxiety is one of the major psychiatric comorbidities in epilepsy patients. However, anxiety in epilepsy patients often remains unrecognized and untreated. It is believed that the inhibitory networks of γ-aminobutyric acid (GABA) neurotransmission play pivotal roles in the modulation of emotion and mood responses in both physiological and pathological conditions. The impairment of neurotransmission mediated by GABAergic signaling is related to the pathophysiology of anxiety. However, it remains unclear whether and how GABAergic signaling modulates anxiety responses in the context of an epileptic brain. In the present study, we sought to determine the role of inhibitory networks of GABAergic signaling in the anxiety-like behavior of epileptic mice. Our results show epileptic mice exhibited increased anxiety-like behavior, and this increased anxiety-like behavior was accompanied by a decrease in GABAergic interneurons and an increase in GABA type A receptor (GABAAR) β3 subunit (GABRB3) expression in the hippocampus. Furthermore, the activation of GABAARs produced an anxiolytic-like effect, while the inhibition of GABAARs elicited an anxiogenic-like effect in the epileptic mice, suggesting that the alteration of GABAergic signaling is associated with anxiety-like behavior in epileptic mice. Thus, targeting GABAergic signaling in the epileptic brain may provide an effective anxiolytic treatment in epilepsy patients.
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Affiliation(s)
- Xinjian Zhu
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China.
| | - Yuanyuan Yao
- Department of Pharmacology, Medical School of Southeast University, Nanjing, China
| | - Xiaolin Li
- Department of Geriatrics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jingde Dong
- Department of Geriatric Neurology, Nanjing Brain Hospital Affiliated with Nanjing Medical University, Nanjing, China
| | - Aifeng Zhang
- Department of Pathology, Medical School of Southeast University, Nanjing, China
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20
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Sgritta M, Dooling SW, Buffington SA, Momin EN, Francis MB, Britton RA, Costa-Mattioli M. Mechanisms Underlying Microbial-Mediated Changes in Social Behavior in Mouse Models of Autism Spectrum Disorder. Neuron 2019; 101:246-259.e6. [PMID: 30522820 PMCID: PMC6645363 DOI: 10.1016/j.neuron.2018.11.018] [Citation(s) in RCA: 415] [Impact Index Per Article: 83.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/18/2018] [Accepted: 11/08/2018] [Indexed: 01/01/2023]
Abstract
Currently, there are no medications that effectively treat the core symptoms of Autism Spectrum Disorder (ASD). We recently found that the bacterial species Lactobacillus (L.) reuteri reverses social deficits in maternal high-fat-diet offspring. However, whether the effect of L. reuteri on social behavior is generalizable to other ASD models and its mechanism(s) of action remains unknown. Here, we found that treatment with L. reuteri selectively rescues social deficits in genetic, environmental, and idiopathic ASD models. Interestingly, the effects of L. reuteri on social behavior are not mediated by restoring the composition of the host's gut microbiome, which is altered in all of these ASD models. Instead, L. reuteri acts in a vagus nerve-dependent manner and rescues social interaction-induced synaptic plasticity in the ventral tegmental area of ASD mice, but not in oxytocin receptor-deficient mice. Collectively, treatment with L. reuteri emerges as promising non-invasive microbial-based avenue to combat ASD-related social dysfunction.
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Affiliation(s)
- Martina Sgritta
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Memory and Brain Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sean W Dooling
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Memory and Brain Research Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shelly A Buffington
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Memory and Brain Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Eric N Momin
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael B Francis
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Memory and Brain Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robert A Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mauro Costa-Mattioli
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Memory and Brain Research Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
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21
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Masiulis S, Desai R, Uchański T, Serna Martin I, Laverty D, Karia D, Malinauskas T, Zivanov J, Pardon E, Kotecha A, Steyaert J, Miller KW, Aricescu AR. GABA A receptor signalling mechanisms revealed by structural pharmacology. Nature 2019; 565:454-459. [PMID: 30602790 PMCID: PMC6370056 DOI: 10.1038/s41586-018-0832-5] [Citation(s) in RCA: 318] [Impact Index Per Article: 63.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/23/2018] [Indexed: 01/02/2023]
Abstract
Type-A γ-aminobutyric (GABAA) receptors are ligand-gated chloride channels with a very rich pharmacology. Some of their modulators, including benzodiazepines and general anaesthetics, are among the most successful drugs in clinical use and are common substances of abuse. Without reliable structural data, the mechanistic basis for the pharmacological modulation of GABAA receptors remains largely unknown. Here we report several high-resolution cryo-electron microscopy structures in which the full-length human α1β3γ2L GABAA receptor in lipid nanodiscs is bound to the channel-blocker picrotoxin, the competitive antagonist bicuculline, the agonist GABA (γ-aminobutyric acid), and the classical benzodiazepines alprazolam and diazepam. We describe the binding modes and mechanistic effects of these ligands, the closed and desensitized states of the GABAA receptor gating cycle, and the basis for allosteric coupling between the extracellular, agonist-binding region and the transmembrane, pore-forming region. This work provides a structural framework in which to integrate previous physiology and pharmacology research and a rational basis for the development of GABAA receptor modulators.
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Affiliation(s)
- Simonas Masiulis
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
| | - Rooma Desai
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tomasz Uchański
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Itziar Serna Martin
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Duncan Laverty
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Dimple Karia
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Jasenko Zivanov
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Abhay Kotecha
- Materials and Structural Analysis, Thermo Fisher Scientific, Eindhoven, The Netherlands
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Keith W Miller
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - A Radu Aricescu
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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22
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Razack S, Kandikattu HK, Venuprasad MP, Amruta N, Khanum F, Chuttani K, Mishra AK. Anxiolytic actions of Nardostachys jatamansi via GABA benzodiazepine channel complex mechanism and its biodistribution studies. Metab Brain Dis 2018; 33:1533-1549. [PMID: 29934858 DOI: 10.1007/s11011-018-0261-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/28/2018] [Indexed: 12/27/2022]
Abstract
Nardostachys jatamansi has profound applications against pharmacological interventions and is categorized as a hypno-sedative drug according to Ayurveda. In the present study probable mechanism of anxiolytic action of Nardostachys jatamansi extract (NJE) was studied using behavioral anxiolytic tests (Elevated plus maze, Open field test, Light dark box test, and Vogel's conflict test) in mice. Mice were treated orally with NJE (250 mg/kg) for 3, 7 and 14 days or diazepam (1 mg/kg) followed by behavioral assessment and estimation of monoamine neurotransmitters, GABA, and antioxidant enzymes. Treatment of mice for 7 days caused an increase in time spent in open arms in elevated plus maze, number of line crossings in open field test, increased time spent in lit compartment of light-dark box test, an increase in number of licks made and shocks accepted in Vogel's conflict test, with results comparable to diazepam and this treatment also caused a significant increase in monoamine neurotransmitters and GABA in brain and tissue antioxidant parameters. Co-treatment of NJE with flumazenil (GABA-benzodiazepine antagonist; 0.5 mg/kg i.p) or picrotoxin (GABAA gated chloride channel blocker; 1 mg/kg i.p) caused a blockage/antagonised anxiolytic actions of NJE by causing a significant reduction in time spent in open arms of elevated plus maze, an decrease in number of line crossing in open field test and also number of shocks and licks accepted in Vogel's conflict test. Further, NJE was radiolabelled with technetium99m at their hydroxyl groups following which purity as well as in vivo and in vitro stability of radiolabelled formulations was evaluated. The blood kinetics and in vivo bio-distribution studies were carried out in rabbits and mice respectively. Labeled formulation was found to be stable in vitro (96 to 93% stability) and in vivo (96 to 92% stability). The labeled compound was cleared rapidly from blood (within 24 h) and accumulated majorly in kidneys (11.65 ± 1.33), liver (6.07 ± 0.94), and blood (4.03 ± 0.63) after 1 h. However, a small amount was observed in brain (0.1 ± 0.02) probably because of its inability to cross blood-brain barrier. These results highlight biodistribution pattern of NJE, and also indicated that a 7-day treatment with NJE produced significant anxiolytic effects in mice and also a significant increase in brain monoamine and GABA neurotransmitter levels and suggests that anxiolytic effects of NJE are primarily and plausibly mediated by activating GABAergic receptor complex.
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Affiliation(s)
- Sakina Razack
- Biochemistry and Nanosciences Discipline, Defence Food Research Laboratory, Mysore, Karnataka, 570011, India.
| | - Hemanth Kumar Kandikattu
- Biochemistry and Nanosciences Discipline, Defence Food Research Laboratory, Mysore, Karnataka, 570011, India
| | - M P Venuprasad
- Biochemistry and Nanosciences Discipline, Defence Food Research Laboratory, Mysore, Karnataka, 570011, India
| | | | - Farhath Khanum
- Biochemistry and Nanosciences Discipline, Defence Food Research Laboratory, Mysore, Karnataka, 570011, India.
| | - Krishna Chuttani
- Department of Pharmaceuticals, Institute of Nuclear Medicine and Allied Sciences, Brigadier Mazumdar Marg, Timar Pur, Delhi, 110054, India
| | - Anil Kumar Mishra
- Department of Pharmaceuticals, Institute of Nuclear Medicine and Allied Sciences, Brigadier Mazumdar Marg, Timar Pur, Delhi, 110054, India
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23
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O'Neill N, Sylantyev S. Spontaneously opening GABA A receptors play a significant role in neuronal signal filtering and integration. Cell Death Dis 2018; 9:813. [PMID: 30042389 PMCID: PMC6057890 DOI: 10.1038/s41419-018-0856-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/18/2018] [Accepted: 06/25/2018] [Indexed: 11/23/2022]
Abstract
Continuous (tonic) charge transfer through ionotropic receptors of γ-aminobutyric acid (GABAARs) is an important mechanism of inhibitory signalling in the brain. The conventional view has been that tonic GABA-ergic inhibitory currents are mediated by low concentrations of ambient GABA. Recently, however, it was shown that the GABA-independent, spontaneously opening GABAARs (s-GABAARs), may contribute significantly to the tonic GABAAR current. One of the common approaches to temporal lobe epilepsy (TLE) therapy is an increase of GABA concentration in the cerebrospinal fluid to augment tonic current through GABAARs. Such an increase, however, generates multiple side effects, which impose significant limitations on the use of correspondent drugs. In contrast, activation/deactivation of s-GABAARs in a GABA-independent manner may provide a mechanism of regulation of tonic conductance without modification of extracellular GABA concentration, thus avoiding connected side effects. Although s-GABAARs have been detected in our earlier work, it is unclear whether they modulate neural signalling, or, due to their independence from the neurotransmitter, they provide just a stable background effect without much impact on neural crosstalk dynamics. Here, we focused on the causal relationship between s-GABAAR activity and signal integration in the rat's dentate gyrus granule cells to find that s-GABAARs play an important role in neural signal transduction. s-GABAARs shape the dynamics of phasic inhibitory responses, regulate the action potential generation machinery and control the coincidence detection window pertinent to excitatory input summation. Our results demonstrate that tonic inhibition delivered by s-GABAARs contributes to the key mechanisms that ensure implementation of neural signal filtering and integration, in a GABA-independent manner. This makes s-GABAAR a new and important actor in the regulation of long-term neural plasticity and a perspective target for TLE therapy.
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Affiliation(s)
- Nathanael O'Neill
- CCBS, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Sergiy Sylantyev
- CCBS, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
- DCEE, Institute of Neurology, University College London, QSH, Queen Square, London, WC1N 3BG, UK.
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24
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Baratta MV, Leslie NR, Fallon IP, Dolzani SD, Chun LE, Tamalunas AM, Watkins LR, Maier SF. Behavioural and neural sequelae of stressor exposure are not modulated by controllability in females. Eur J Neurosci 2018; 47:959-967. [PMID: 29359831 PMCID: PMC5902414 DOI: 10.1111/ejn.13833] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 01/08/2018] [Accepted: 01/10/2018] [Indexed: 12/12/2022]
Abstract
The degree of behavioural control that an organism has over a stressor is a potent modulator of the stressor's impact; controllable stressors produce none of the neurochemical and behavioural sequelae that occur if the stressor is uncontrollable. Research demonstrating the importance of control and the neural mechanisms responsible has been conducted almost entirely with male rats. It is unknown if behavioural control is stress blunting in females, and whether or not a similar resilience circuitry is engaged. Female rats were exposed to controllable, yoked uncontrollable or no tailshock. In separate experiments, behavioural (juvenile social exploration, fear and shuttle box escape) and neurochemical (activation of dorsal raphe serotonin and dorsal raphe-projecting prelimbic neurons) outcomes, which are sensitive to the dimension of control in males, were assessed. Despite successful acquisition of the controlling response, behavioural control did not mitigate dorsal raphe serotonergic activation and behavioural outcomes induced by tailshock, as it does in males. Moreover, behavioural control failed to selectively engage prelimbic cells that project to the dorsal raphe as in males. Pharmacological activation of the prelimbic cortex restored the stress-buffering effects of control. Collectively, the data demonstrate stressor controllability phenomena are absent in females and that the protective prelimbic circuitry is present but not engaged. Reduced benefit from coping responses may represent a novel approach for understanding differential sex prevalence in stress-related psychiatric disorders.
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Affiliation(s)
- Michael V. Baratta
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Nathan R. Leslie
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Isabella P. Fallon
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Samuel D. Dolzani
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
- Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, Colorado, USA
| | - Lauren E. Chun
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Andrew M. Tamalunas
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Linda R. Watkins
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
| | - Steven F. Maier
- Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, USA
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25
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Ghosh B, Tsao TW, Czajkowski C. A chimeric prokaryotic-eukaryotic pentameric ligand gated ion channel reveals interactions between the extracellular and transmembrane domains shape neurosteroid modulation. Neuropharmacology 2017; 125:343-352. [PMID: 28803966 PMCID: PMC5600277 DOI: 10.1016/j.neuropharm.2017.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/30/2017] [Accepted: 08/08/2017] [Indexed: 10/19/2022]
Abstract
Pentameric ligand-gated ion channels (pLGICs) are the targets of several clinical and endogenous allosteric modulators including anesthetics and neurosteroids. Molecular mechanisms underlying allosteric drug modulation are poorly understood. Here, we constructed a chimeric pLGIC by fusing the extracellular domain (ECD) of the proton-activated, cation-selective bacterial channel GLIC to the transmembrane domain (TMD) of the human ρ1 chloride-selective GABAAR, and tested the hypothesis that drug actions are regulated locally in the domain that houses its binding site. The chimeric channels were proton-gated and chloride-selective demonstrating the GLIC ECD was functionally coupled to the GABAρ TMD. Channels were blocked by picrotoxin and inhibited by pentobarbital, etomidate and propofol. The point mutation, ρ TMD W328M, conferred positive modulation and direct gating by pentobarbital. The data suggest that the structural machinery mediating general anesthetic modulation resides in the TMD. Proton-activation and neurosteroid modulation of the GLIC-ρ chimeric channels, however, did not simply mimic their respective actions on GLIC and GABAρ revealing that across domain interactions between the ECD and TMD play important roles in determining their actions. Proton-induced current responses were biphasic suggesting that the chimeric channels contain an additional proton sensor. Neurosteroid modulation of the GLIC-ρ chimeric channels by the stereoisomers, 5α-THDOC and 5β-THDOC, were swapped compared to their actions on GABAρ indicating that positive versus negative neurosteroid modulation is not encoded solely in the TMD nor by neurosteroid isomer structure but is dependent on specific interdomain connections between the ECD and TMD. Our data reveal a new mechanism for shaping neurosteroid modulation.
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Affiliation(s)
- Borna Ghosh
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin - Madison, 1111 Highland Ave, Madison, WI 53705, USA; Eli Lilly and Company, 1220 W Morris St, Indianapolis, IN 46221, USA
| | - Tzu-Wei Tsao
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin - Madison, 1111 Highland Ave, Madison, WI 53705, USA; Physiology Training Program, University of Wisconsin - Madison, 1111 Highland Ave, Madison, WI 53705, USA
| | - Cynthia Czajkowski
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin - Madison, 1111 Highland Ave, Madison, WI 53705, USA.
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Boulanger JJ, Messier C. Oligodendrocyte progenitor cells are paired with GABA neurons in the mouse dorsal cortex: Unbiased stereological analysis. Neuroscience 2017; 362:127-140. [PMID: 28827179 DOI: 10.1016/j.neuroscience.2017.08.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 11/17/2022]
Abstract
Oligodendrocyte progenitor cells (OPC) are glial cells that differentiate into myelinating oligodendrocytes during early stages of post-natal life. However, OPCs persist beyond developmental myelination and represent an important population of cycling cells in the gray and white matter of the adult brain. While adult OPCs form unique territories that are maintained through self-avoidance, some cortical OPCs appear to position their cell body very close to that of a neuron, forming what are known as OPC-neuron pairs. We used unbiased systematic stereological analysis of the NG2-CreERTM:EYFP reporter mouse to determine that close to 170,000 OPC-neuron pairs can be found in the dorsal portion of the adult neocortex, with approximately 40% of OPCs and 4% of neurons in pairs. Through stereological analysis, we also determined that reference memory training does not change the prevalence of OPC-neuron pairs or the proportion of OPCs and neurons that form them. GABAergic agent administration did not affect the proportion of OPCs and neurons that can be found in pairs. However, the GABAB-receptor agonist baclofen and the GABAA receptor antagonist picrotoxin significantly increased the estimated number of pairs when compared to the control group and the GABAB-receptor antagonist (i.e. saclofen) group. Density of OPC-neuron pairs was increased by the GABAA receptor antagonist picrotoxin. Finally, histological analysis of OPC-neuron pairs suggested that in the dorsal portion of the cortex, GABAergic interneurons represent the most common neuronal component of the pairs, and that calbindin, calretinin and parvalbumin GABAergic interneurons found in the cortex take part in these pairs. Using previous estimates of the number of GABAergic neurons in the rodent cortex, we estimate that roughly one in four GABAergic neurons are paired with an OPC.
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Wu SF, Mu XC, Dong YX, Wang LX, Wei Q, Gao CF. Expression pattern and pharmacological characterisation of two novel alternative splice variants of the glutamate-gated chloride channel in the small brown planthopper Laodelphax striatellus. Pest Manag Sci 2017; 73:590-597. [PMID: 27302648 DOI: 10.1002/ps.4340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Glutamate-gated chloride channels (GluCl) mediate fast inhibitory neurotransmission in invertebrate nervous systems. Although only one GluCl gene was presented in insects, it showed diverse alternative splicing that was speculated could affect channel function and pharmacology. RESULTS In this study, we isolated GluCl cDNAs from adults of the small brown planthopper (SBPH) Laodelphax striatellus and showed that six L. striatellus GluCl variants (LsGluCl-AS, LsGluCl-BS, LsGluCl-CS, LsGluCl-AL, LsGluCl-BL, LsGluCl-CL) were present in the SBPH. The expression patterns of six variants differed among developmental stages (egg, first- to fifth-instar nymphs, male and female adults) and among the body parts (head, thorax, abdomen, leg) of the female adult SBPH. All the transcripts were abundant in the head of the adult. When expressed in African clawed frog, Xenopus laevis, oocytes, the two functional variants (LsGluCl-AS, LsGluCl-AL) had similar EC50 and IC50 values for L-glutamate and channel blockers picrotoxinin and fipronil. CONCLUSION This study represents a comprehensive molecular, expression and pharmacological characterisation of GluCl in the SBPH. These findings should be useful in providing more opportunities to discover novel insect control chemicals. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Shun-Fan Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State and Local Joint Engineering Research Centre of Green Pesticide Invention and Application, Jiangsu, China
| | - Xi-Chao Mu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State and Local Joint Engineering Research Centre of Green Pesticide Invention and Application, Jiangsu, China
| | - Yao-Xue Dong
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State and Local Joint Engineering Research Centre of Green Pesticide Invention and Application, Jiangsu, China
| | - Li-Xiang Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State and Local Joint Engineering Research Centre of Green Pesticide Invention and Application, Jiangsu, China
| | - Qi Wei
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State and Local Joint Engineering Research Centre of Green Pesticide Invention and Application, Jiangsu, China
| | - Cong-Fen Gao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- State and Local Joint Engineering Research Centre of Green Pesticide Invention and Application, Jiangsu, China
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28
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Radzicki D, Pollema-Mays SL, Sanz-Clemente A, Martina M. Loss of M1 Receptor Dependent Cholinergic Excitation Contributes to mPFC Deactivation in Neuropathic Pain. J Neurosci 2017; 37:2292-2304. [PMID: 28137966 PMCID: PMC5354343 DOI: 10.1523/jneurosci.1553-16.2017] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 12/01/2016] [Accepted: 01/05/2017] [Indexed: 11/21/2022] Open
Abstract
In chronic pain, the medial prefrontal cortex (mPFC) is deactivated and mPFC-dependent tasks such as attention and working memory are impaired. We investigated the mechanisms of mPFC deactivation in the rat spared nerve injury (SNI) model of neuropathic pain. Patch-clamp recordings in acute slices showed that, 1 week after the nerve injury, cholinergic modulation of layer 5 (L5) pyramidal neurons was severely impaired. In cells from sham-operated animals, focal application of acetylcholine induced a left shift of the input/output curve and persistent firing. Both of these effects were almost completely abolished in cells from SNI-operated rats. The cause of this impairment was an ∼60% reduction of an M1-coupled, pirenzepine-sensitive depolarizing current, which appeared to be, at least in part, the consequence of M1 receptor internalization. Although no changes were detected in total M1 protein or transcript, both the fraction of the M1 receptor in the synaptic plasma membrane and the biotinylated M1 protein associated with the total plasma membrane were decreased in L5 mPFC of SNI rats. The loss of excitatory cholinergic modulation may play a critical role in mPFC deactivation in neuropathic pain and underlie the mPFC-specific cognitive deficits that are comorbid with neuropathic pain.SIGNIFICANCE STATEMENT The medial prefrontal cortex (mPFC) undergoes major reorganization in chronic pain. Deactivation of mPFC output is causally correlated with both the cognitive and the sensory component of neuropathic pain. Here, we show that cholinergic excitation of commissural layer 5 mPFC pyramidal neurons is abolished in neuropathic pain rats due to a severe reduction of a muscarinic depolarizing current and M1 receptor internalization. Therefore, in neuropathic pain rats, the acetylcholine (ACh)-dependent increase in neuronal excitability is reduced dramatically and the ACh-induced persisting firing, which is critical for working memory, is abolished. We propose that the blunted cholinergic excitability contributes to the functional mPFC deactivation that is causal for the pain phenotype and represents a cellular mechanism for the attention and memory impairments comorbid with chronic pain.
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Affiliation(s)
| | | | - Antonio Sanz-Clemente
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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Hasebe S, Ago Y, Watabe Y, Oka S, Hiramatsu N, Tanaka T, Umehara C, Hashimoto H, Takuma K, Matsuda T. Anti-anhedonic effect of selective serotonin reuptake inhibitors with affinity for sigma-1 receptors in picrotoxin-treated mice. Br J Pharmacol 2017; 174:314-327. [PMID: 27987210 PMCID: PMC5289945 DOI: 10.1111/bph.13692] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/07/2016] [Accepted: 12/09/2016] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Prefrontal dopamine release by the combined activation of 5-HT1A and sigma-1 (σ1 ) receptors is enhanced by the GABAA receptor antagonist picrotoxin in mice. Here, we examined whether this neurochemical event was accompanied by behavioural changes. EXPERIMENTAL APPROACH Male mice were treated with picrotoxin to decrease GABAA receptor function. Their anhedonic behaviour was measured using the female encounter test. The expression of c-Fos was determined immunohistochemically. KEY RESULTS Picrotoxin caused an anxiogenic effect on three behavioural tests, but it did not affect the immobility time in the forced swim test. Picrotoxin decreased female preference in the female encounter test and attenuated the female encounter-induced increase in c-Fos expression in the nucleus accumbens. Picrotoxin-induced anhedonia was ameliorated by fluvoxamine and S-(+)-fluoxetine, selective serotonin reuptake inhibitors with high affinity for the σ1 receptor. The effect of fluvoxamine was blocked by a 5-HT1A or a σ1 receptor antagonist, and co-administration of the σ1 receptor agonist (+)-SKF-10047 and the 5-HT1A receptor agonist osemozotan mimicked the effect of fluvoxamine. By contrast, desipramine, duloxetine and paroxetine, which have little affinity for the σ1 receptor, did not affect picrotoxin-induced anhedonia. The effect of fluvoxamine was blocked by a dopamine D2/3 receptor antagonist. Methylphenidate, an activator of the prefrontal dopamine system, ameliorated picrotoxin-induced anhedonia. CONCLUSION AND IMPLICATIONS Picrotoxin-treated mice show anhedonic behaviour that is ameliorated by simultaneous activation of 5-HT1A and σ1 receptors. These findings suggest that the increased prefrontal dopamine release is associated with the anti-anhedonic effect observed in picrotoxin-treated mice.
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Affiliation(s)
- S Hasebe
- Department of Pharmacology, Graduate School of DentistryOsaka UniversityOsakaJapan
| | - Y Ago
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - Y Watabe
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - S Oka
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - N Hiramatsu
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - T Tanaka
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - C Umehara
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
| | - H Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
- United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of FukuiOsakaJapan
- Division of Bioscience, Institute for Datability ScienceOsaka UniversityOsakaJapan
| | - K Takuma
- Department of Pharmacology, Graduate School of DentistryOsaka UniversityOsakaJapan
- United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of FukuiOsakaJapan
| | - T Matsuda
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical SciencesOsaka UniversityOsakaJapan
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Ago Y, Hasebe S, Hiramatsu N, Mori K, Watabe Y, Onaka Y, Hashimoto H, Takuma K, Matsuda T. Involvement of GABAA receptors in 5-HT1A and σ1 receptor synergism on prefrontal dopaminergic transmission under circulating neurosteroid deficiency. Psychopharmacology (Berl) 2016; 233:3125-34. [PMID: 27339616 DOI: 10.1007/s00213-016-4353-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/09/2016] [Indexed: 12/29/2022]
Abstract
RATIONALE We previously reported that the fluvoxamine-induced increase in prefrontal dopamine levels is enhanced by adrenalectomy/castration (which results in circulating neurosteroid deficiency), via combined activation of serotonin1A (5-HT1A) and σ1 receptors. However, the mechanistic details of the interaction between 5-HT1A and σ1 receptors are unknown. OBJECTIVES Because most neurosteroids have affinity for γ-aminobutyric acid (GABA)A receptors, in the present study, we examined the involvement of GABAA receptors in this process. RESULTS Adrenalectomy/castration decreased pentobarbital-induced sleeping time in mice, suggesting that it reduced GABAA receptor function. The GABAA receptor antagonist picrotoxin (1 mg/kg) enhanced the fluvoxamine-induced increase in prefrontal dopamine, but not noradrenaline or serotonin, levels in mice, suggesting that picrotoxin mimicked the effect of adrenalectomy/castration. Picrotoxin also potentiated the increase in prefrontal dopamine levels mediated by co-administration of the 5-HT1A receptor agonist osemozotan and the σ1 receptor agonist (+)-SKF-10,047, while it did not affect the co-administration-induced changes in noradrenaline and serotonin levels. Conversely, the GABAA receptor agonist diazepam (1 mg/kg) blocked the effect of adrenalectomy/castration on the fluvoxamine-induced increase in prefrontal dopamine levels. Co-administration of osemozotan and (+)-SKF-10,047 did not affect the expression of the neuronal activity marker c-Fos in the prefrontal cortex, ventral tegmental area, and nucleus accumbens in control mice, while it increased the c-Fos expression only in the prefrontal cortex and ventral tegmental area in picrotoxin-treated mice. CONCLUSIONS These results suggest that the GABAA receptor plays a key role in mediating the synergistic effects of 5-HT1A and σ1 receptor activation on prefrontal dopamine neurotransmission.
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Affiliation(s)
- Yukio Ago
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Shigeru Hasebe
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Naoki Hiramatsu
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Kazuya Mori
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yuji Watabe
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yusuke Onaka
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Hitoshi Hashimoto
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan
- United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Kazuhiro Takuma
- Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamada-oka, Suita, Osaka, 565-0871, Japan
- United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Toshio Matsuda
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka, 565-0871, Japan.
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Camargo G, Elizalde A, Trujillo X, Montoya-Pérez R, Mendoza-Magaña ML, Hernandez-Chavez A, Hernandez L. Inactivation of GABAA receptor is related to heat shock stress response in organism model Caenorhabditis elegans. Cell Stress Chaperones 2016; 21:763-72. [PMID: 27230213 PMCID: PMC5003793 DOI: 10.1007/s12192-016-0701-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/29/2016] [Accepted: 05/11/2016] [Indexed: 01/08/2023] Open
Abstract
The mechanisms underlying oxidative stress (OS) resistance are not completely clear. Caenorhabditis elegans (C. elegans) is a good organism model to study OS because it displays stress responses similar to those in mammals. Among these mechanisms, the insulin/IGF-1 signaling (IIS) pathway is thought to affect GABAergic neurotransmission. The aim of this study was to determine the influence of heat shock stress (HS) on GABAergic activity in C. elegans. For this purpose, we tested the effect of exposure to picrotoxin (PTX), gamma-aminobutyric acid (GABA), hydrogen peroxide, and HS on the occurrence of a shrinking response (SR) after nose touch stimulus in N2 (WT) worms. Moreover, the effect of HS on the expression of UNC-49 (GABAA receptor ortholog) in the EG1653 strain and the effect of GABA and PTX exposure on HSP-16.2 expression in the TJ375 strain were analyzed. PTX 1 mM- or H2O2 0.7 mM-exposed worms displayed a SR in about 80 % of trials. GABA exposure did not cause a SR. HS prompted the occurrence of a SR as did PTX 1 mM or H2O2 0.7 mM exposure. In addition, HS increased UNC-49 expression, and PTX augmented HSP-16.2 expression. Thus, the results of the present study suggest that oxidative stress, through either H2O2 exposure or application of heat shock, inactivates the GABAergic system, which subsequently would affect the oxidative stress response, perhaps by enhancing the activity of transcription factors DAF-16 and HSF-1, both regulated by the IIS pathway and related to hsp-16.2 expression.
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Affiliation(s)
- Gabriela Camargo
- Laboratorio de Neurofisiología, Departamento de Fisiología, Centro Universitario de Ciencias dela Salud, Universidad de Guadalajara, Sierra Mojada # 950, Guadalajara, 44340, Jalisco, Mexico
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Av. 25 de Julio # 965, Colima, 28045, Colima, Mexico
- Laboratorio de Biotecnología, Departamento de Botánica y Zoología, Centro Universitariode Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Camino Ramón Padilla Sánchez # 2100, Zapopan, 45110, Jalisco, Mexico
| | - Alejandro Elizalde
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Av. 25 de Julio # 965, Colima, 28045, Colima, Mexico
| | - Xochitl Trujillo
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Av. 25 de Julio # 965, Colima, 28045, Colima, Mexico
| | - Rocío Montoya-Pérez
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Francisco J. Mújica S/N, Morelia, 58030, Michoacán, Mexico
| | - María Luisa Mendoza-Magaña
- Laboratorio de Neurofisiología, Departamento de Fisiología, Centro Universitario de Ciencias dela Salud, Universidad de Guadalajara, Sierra Mojada # 950, Guadalajara, 44340, Jalisco, Mexico
| | - Abel Hernandez-Chavez
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, SierraMojada # 950, Guadalajara, 44340, Jalisco, Mexico
| | - Leonardo Hernandez
- Laboratorio de Neurofisiología, Departamento de Fisiología, Centro Universitario de Ciencias dela Salud, Universidad de Guadalajara, Sierra Mojada # 950, Guadalajara, 44340, Jalisco, Mexico.
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Laprell L, Hüll K, Stawski P, Schön C, Michalakis S, Biel M, Sumser MP, Trauner D. Restoring Light Sensitivity in Blind Retinae Using a Photochromic AMPA Receptor Agonist. ACS Chem Neurosci 2016; 7:15-20. [PMID: 26495755 PMCID: PMC4722500 DOI: 10.1021/acschemneuro.5b00234] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 10/23/2015] [Indexed: 12/15/2022] Open
Abstract
Retinal degenerative diseases can have many possible causes and are currently difficult to treat. As an alternative to therapies that require genetic manipulation or the implantation of electronic devices, photopharmacology has emerged as a viable approach to restore visual responses. Here, we present a new photopharmacological strategy that relies on a photoswitchable excitatory amino acid, ATA. This freely diffusible molecule selectively activates AMPA receptors in a light-dependent fashion. It primarily acts on amacrine and retinal ganglion cells, although a minor effect on bipolar cells has been observed. As such, it complements previous pharmacological approaches based on photochromic channel blockers and increases the potential of photopharmacology in vision restoration.
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Affiliation(s)
- L. Laprell
- Center
of Integrated Protein Science Munich (CIPSM) at the Department of
Chemistry Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - K. Hüll
- Center
of Integrated Protein Science Munich (CIPSM) at the Department of
Chemistry Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - P. Stawski
- Center
of Integrated Protein Science Munich (CIPSM) at the Department of
Chemistry Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - C. Schön
- Center
for Integrated Protein Science Munich (CIPSM) at the Department of
Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - S. Michalakis
- Center
for Integrated Protein Science Munich (CIPSM) at the Department of
Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - M Biel
- Center
for Integrated Protein Science Munich (CIPSM) at the Department of
Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - M. P. Sumser
- Center
of Integrated Protein Science Munich (CIPSM) at the Department of
Chemistry Ludwig-Maximilians-Universität
München, Munich 81377, Germany
| | - D. Trauner
- Center
of Integrated Protein Science Munich (CIPSM) at the Department of
Chemistry Ludwig-Maximilians-Universität
München, Munich 81377, Germany
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Allio A, Calorio C, Franchino C, Gavello D, Carbone E, Marcantoni A. Bud extracts from Tilia tomentosa Moench inhibit hippocampal neuronal firing through GABAA and benzodiazepine receptors activation. J Ethnopharmacol 2015; 172:288-296. [PMID: 26144285 DOI: 10.1016/j.jep.2015.06.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/10/2015] [Accepted: 06/14/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Tilia tomentosa Moench bud extracts (TTBEs) is used in traditional medicine for centuries as sedative compound. Different plants belonging to the Tilia genus have shown their efficacy in the treatment of anxiety but still little is known about the mechanism of action of their bud extracts. AIM OF THE STUDY To evaluate the action of TTBEs as anxiolytic and sedative compound on in vitro hippocampal neurons. MATERIAL AND METHODS The anxiolytic effect of TTBEs was assayed by testing the effects of these compounds on GABAA receptor-activated chloride current of hippocampal neurons by means of the patch-clamp technique and microelectrode-arrays (MEAs). RESULTS TTBEs acutely administered on mouse hippocampal neurons, activated a chloride current comparable to that measured in the presence of GABA (100 µM). Bicuculline (100 µM) and picrotoxin (100 µM) blocked about 90% of this current, while the remaining 10% was blocked by adding the benzodiazepine (BDZ) antagonist flumazenil (30 µM). Flumazenil alone blocked nearly 60% of the TTBEs activated current, suggesting that TTBEs binds to both GABAA and BDZ receptor sites. Application of high-doses of TTBEs on spontaneous active hippocampal neurons grown for 3 weeks on MEAs blocked the synchronous activity of these neurons. The effects were mimicked by GABA and prevented by picrotoxin (100µM) and flumazenil (30 µM). At minimal doses, TTBEs reduced the frequency of synchronized bursts and increased the cross-correlation index of synchronized neuronal firing. CONCLUSIONS Our data suggest that TTBEs mimics GABA and BDZ agonists by targeting hippocampal GABAergic synapses and inhibiting network excitability by increasing the strength of inhibitory synaptic outputs. Our results contribute toward the validation of TTBEs as effective sedative and anxiolytic compound.
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Affiliation(s)
- Arianna Allio
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Chiara Calorio
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Claudio Franchino
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Daniela Gavello
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Emilio Carbone
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
| | - Andrea Marcantoni
- Department of Drug Science and Technology, University of Torino, Corso Raffaello 30, 10125 Torino, Italy.
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Rodgers FC, Zarnowska ED, Laha KT, Engin E, Zeller A, Keist R, Rudolph U, Pearce RA. Etomidate Impairs Long-Term Potentiation In Vitro by Targeting α5-Subunit Containing GABAA Receptors on Nonpyramidal Cells. J Neurosci 2015; 35:9707-16. [PMID: 26134653 PMCID: PMC4571505 DOI: 10.1523/jneurosci.0315-15.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 05/07/2015] [Accepted: 05/28/2015] [Indexed: 02/07/2023] Open
Abstract
Previous experiments using genetic and pharmacological manipulations have provided strong evidence that etomidate impairs synaptic plasticity and memory by modulating α5-subunit containing GABAA receptors (α5-GABAARs). Because α5-GABAARs mediate tonic inhibition (TI) in hippocampal CA1 pyramidal cells and etomidate enhances TI, etomidate enhancement of TI in pyramidal cells has been proposed as the underlying mechanism (Martin et al., 2009). Here we tested this hypothesis by selectively removing α5-GABAARs from pyramidal neurons (CA1-pyr-α5-KO) and comparing the ability of etomidate to enhance TI and block LTP in fl-α5 (WT), global-α5-KO (gl-α5-KO), and CA1-pyr-α5-KO mice. Etomidate suppressed LTP in slices from WT and CA1-pyr-α5-KO but not gl-α5-KO mice. There was a trend toward reduced TI in both gl-α5-KO and CA1-pyr-α5-KO mice, but etomidate enhanced TI to similar levels in all genotypes. The dissociation between effects of etomidate on TI and LTP in gl-α5-KO mice indicates that increased TI in pyramidal neurons is not the mechanism by which etomidate impairs LTP and memory. Rather, the ability of etomidate to block LTP in WT and CA1-pyr-α5-KO mice, but not in gl-α5-KO mice, points toward α5-GABAARs on nonpyramidal cells as the essential effectors controlling plasticity in this in vitro model of learning and memory.
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Affiliation(s)
- F Clifford Rodgers
- Neuroscience Training Program and Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Ewa D Zarnowska
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Kurt T Laha
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Elif Engin
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, Massachusetts 02478, Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02215, and
| | - Anja Zeller
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Ruth Keist
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital, Belmont, Massachusetts 02478, Department of Psychiatry, Harvard Medical School, Boston, Massachusetts 02215, and
| | - Robert A Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin 53706,
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Larsen L, Joyce NI, Sansom CE, Cooney JM, Jensen DJ, Perry NB. Sweet Poisons: Honeys Contaminated with Glycosides of the Neurotoxin Tutin. J Nat Prod 2015; 78:1363-9. [PMID: 25993882 DOI: 10.1021/acs.jnatprod.5b00241] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Poisonings due to consumption of honeys containing plant toxins have been reported widely. One cause is the neurotoxin tutin, an oxygenated sesquiterpene picrotoxane, traced back to honeybees (Apis mellifera) collecting honeydew produced by passionvine hoppers (Scolypopa australis) feeding on sap of the poisonous shrub tutu (Coriaria spp.). However, a pharmacokinetic study suggested that unidentified conjugates of tutin were also present in such honeys. We now report the discovery, using ion trap LC-MS, of two tutin glycosides and their purification and structure determination as 2-(β-d-glucopyranosyl)tutin (4) and 2-[6'-(α-d-glucopyranosyl)-β-d-glucopyranosyl]tutin (5). These compounds were used to develop a quantitative triple quadrupole LC-MS method for honey analysis, which showed the presence of tutin (3.6 ± 0.1 μg/g honey), hyenanchin (19.3 ± 0.5), tutin glycoside (4) (4.9 ± 0.4), and tutin diglycoside (5) (4.9 ± 0.1) in one toxic honey. The ratios of 4 and 5 to tutin varied widely in other tutin-containing honeys. The glycosidation of tutin may represent detoxification by one or both of the insects involved in the food chain from plant to honey.
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Affiliation(s)
- Lesley Larsen
- †The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Nigel I Joyce
- ‡The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch, New Zealand
| | - Catherine E Sansom
- †The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Janine M Cooney
- §The New Zealand Institute for Plant and Food Research Limited, Hamilton 3214, New Zealand
| | - Dwayne J Jensen
- §The New Zealand Institute for Plant and Food Research Limited, Hamilton 3214, New Zealand
| | - Nigel B Perry
- †The New Zealand Institute for Plant and Food Research Limited, Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, New Zealand
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Sullivan EM, Timi P, Hong LE, O'Donnell P. Effects of NMDA and GABA-A Receptor Antagonism on Auditory Steady-State Synchronization in Awake Behaving Rats. Int J Neuropsychopharmacol 2015; 18:pyu118. [PMID: 25556198 PMCID: PMC4540097 DOI: 10.1093/ijnp/pyu118] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/29/2014] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The auditory steady-state response, which measures the ability of neural ensembles to entrain to rhythmic auditory stimuli, has been used in human electroencephalogram studies to assess sensory processing and electrical oscillatory deficits. Patients with schizophrenia show a deficit in auditory steady-state response at 40 Hz, and therefore this may be a useful biomarker to study this disorder. METHODS We used auditory steady-state response recordings from the primary auditory cortex, hippocampus, and vertex electroencephalogram sites in awake behaving rats to determine whether pharmacological impairment of excitatory or inhibitory neurotransmission mimics auditory steady-state response abnormalities in schizophrenia. RESULTS We found the most robust response to auditory stimuli in the primary auditory cortex, in line with previous studies suggesting this region is the primary generator of the auditory steady-state response in humans. Acute MK-801 (0.1mg/kg i.p.) increased primary auditory cortex intertrial coherence during auditory steady-state response at 20 and 40 Hz. Chronic MK-801 (21-day exposure at this daily dose) had no significant effect on 40-Hz auditory steady-state response. Furthermore, we found no effect of acute or chronic picrotoxin (a GABA-A antagonist) on intertrial coherence. CONCLUSIONS Our data indicate that acute N-methyl-d-aspartate receptor antagonism increases synchronous activity in the primary auditory cortex in a frequency-specific manner, supporting the widely held view that acute N-methyl-d-aspartate antagonism augments gamma oscillations. Thus, rodent auditory steady-state response could be a valuable method to study the cortical ability to support synchronous activity at specific frequencies.
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Affiliation(s)
- Elyse M Sullivan
- Department of Anatomy and Neurobiology (Drs Sullivan and O'Donnell, Ms Timi), Department of Psychiatry (Drs Hong and O'Donnell), and Maryland Psychiatric Research Center (Dr Hong), Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD; Current affiliation: Neuroscience Research Unit, Pfizer, Inc, Cambridge, MA (Dr O'Donnell)
| | - Patricia Timi
- Department of Anatomy and Neurobiology (Drs Sullivan and O'Donnell, Ms Timi), Department of Psychiatry (Drs Hong and O'Donnell), and Maryland Psychiatric Research Center (Dr Hong), Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD; Current affiliation: Neuroscience Research Unit, Pfizer, Inc, Cambridge, MA (Dr O'Donnell)
| | - L Elliot Hong
- Department of Anatomy and Neurobiology (Drs Sullivan and O'Donnell, Ms Timi), Department of Psychiatry (Drs Hong and O'Donnell), and Maryland Psychiatric Research Center (Dr Hong), Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD; Current affiliation: Neuroscience Research Unit, Pfizer, Inc, Cambridge, MA (Dr O'Donnell)
| | - Patricio O'Donnell
- Department of Anatomy and Neurobiology (Drs Sullivan and O'Donnell, Ms Timi), Department of Psychiatry (Drs Hong and O'Donnell), and Maryland Psychiatric Research Center (Dr Hong), Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD; Current affiliation: Neuroscience Research Unit, Pfizer, Inc, Cambridge, MA (Dr O'Donnell).
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Ko MC, Lee MC, Amstislavskaya TG, Tikhonova MA, Yang YL, Lu KT. Inhibition of NKCC1 attenuated hippocampal LTP formation and inhibitory avoidance in rat. PLoS One 2014; 9:e106692. [PMID: 25369049 PMCID: PMC4219661 DOI: 10.1371/journal.pone.0106692] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 08/08/2014] [Indexed: 11/18/2022] Open
Abstract
The loop diuretic bumetanide (Bumex) is thought to have antiepileptic properties via modulate GABAA mediated signaling through their antagonism of cation-chloride cotransporters. Given that loop diuretics may act as antiepileptic drugs that modulate GABAergic signaling, we sought to investigate whether they also affect hippocampal function. The current study was performed to evaluate the possible role of NKCC1 on the hippocampal function. Brain slice extracellular recording, inhibitory avoidance, and western blot were applied in this study. Results showed that hippocampal Long-term potentiation was attenuated by suprafusion of NKCC1 inhibitor bumetanide, in a dose dependent manner. Sequent experiment result showed that Intravenous injection of bumetanide (15.2 mg/kg) 30 min prior to the training session blocked inhibitory avoidance learning significantly. Subsequent control experiment's results excluded the possible non-specific effect of bumetanide on avoidance learning. We also found the phosphorylation of hippocampal MAPK was attenuated after bumetanide administration. These results suggested that hippocampal NKCC1 may via MAPK signaling cascade to possess its function.
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Affiliation(s)
- Meng Chang Ko
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Min Chong Lee
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Tamara G. Amstislavskaya
- Laboratory of Biological Psychiatry, State Research Institute of Physiology and Fundamental Medicine SB RAMS, Novosibirsk, Russia
| | - Maria A. Tikhonova
- Laboratory of Biological Psychiatry, State Research Institute of Physiology and Fundamental Medicine SB RAMS, Novosibirsk, Russia
| | - Yi-Ling Yang
- Department of Biochemical Science and Technology, National Chia-Yi University, Chia-Yi, Taiwan
| | - Kwok-Tung Lu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
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Chiang CC, Ladas TP, Gonzalez-Reyes LE, Durand DM. Seizure suppression by high frequency optogenetic stimulation using in vitro and in vivo animal models of epilepsy. Brain Stimul 2014; 7:890-9. [PMID: 25108607 PMCID: PMC4259846 DOI: 10.1016/j.brs.2014.07.034] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/17/2014] [Accepted: 07/13/2014] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Electrical high frequency stimulation (HFS) has been shown to suppress seizures. However, the mechanisms of seizure suppression remain unclear and techniques for blocking specific neuronal populations are required. OBJECTIVE The goal is to study the optical HFS protocol on seizures as well as the underlying mechanisms relevant to the HFS-mediated seizure suppression by using optogenetic methodology. METHODS Thy1-ChR2 transgenic mice were used in both vivo and in vitro experiments. Optical stimulation with pulse trains at 20 and 50 Hz was applied on the focus to determine its effects on in vivo seizure activity induced by 4-AP and recorded in the bilateral and ipsilateral-temporal hippocampal CA3 regions. In vitro methodology was then used to study the mechanisms of the in vivo suppression. RESULTS Optical HFS was able to generate 82.4% seizure suppression at 50 Hz with light power of 6.1 mW and 80.2% seizure suppression at 20 Hz with light power of 2.0 mW. The suppression percentage increased by increasing the light power and saturated when the power reached above-mentioned values. In vitro experimental results indicate that seizure suppression was mediated by activation of GABA receptors. Seizure suppression effect decreased with continued application but the suppression effect could be restored by intermittent stimulation. CONCLUSIONS This study shows that optical stimulation at high frequency targeting an excitatory opsin has potential therapeutic application for fast control of an epileptic focus. Furthermore, electrophysiological observations of extracellular and intracellular signals revealed that GABAergic neurotransmission activated by optical stimulation was responsible for the suppression.
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Affiliation(s)
- Chia-Chu Chiang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Thomas P Ladas
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Luis E Gonzalez-Reyes
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Dominique M Durand
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
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Mareš P, Kubová H. GABAB, not GABAA receptors play a role in cortical postictal refractoriness. Neuropharmacology 2014; 88:99-102. [PMID: 25229720 DOI: 10.1016/j.neuropharm.2014.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 08/30/2014] [Accepted: 09/04/2014] [Indexed: 11/17/2022]
Abstract
Postictal refractoriness may be taken as an expression of lasting activity of inhibitory systems arresting seizures. We tested drugs interfering with GABAergic inhibitory system in pairs of cortical epileptic afterdischarges induced with 1-min interval in rats. Under control conditions the second stimulation failed to elicit an afterdischarge. This postictal refractoriness was not affected by antagonists of GABAA receptors acting at three binding sites (bicuculline, picrotoxin, benzodiazepine inverse agonist Ro 19-4603) as well as by a less specific antagonist pentetrazol. In contrast, antagonist of GABAB receptors CGP35348 partially blocked the refractoriness. Cooperation of different inhibitory systems is probably necessary to abolish postictal refractoriness in neocortex. This article is part of the Special Issue entitled 'GABAergic Signaling in Health and Disease'.
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Affiliation(s)
- Pavel Mareš
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| | - Hana Kubová
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Xia Y, Zhao Y, Yang M, Zeng S, Shu Y. Regulation of action potential waveforms by axonal GABAA receptors in cortical pyramidal neurons. PLoS One 2014; 9:e100968. [PMID: 24971996 PMCID: PMC4074163 DOI: 10.1371/journal.pone.0100968] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 05/30/2014] [Indexed: 01/11/2023] Open
Abstract
GABAA receptors distributed in somatodendritic compartments play critical roles in regulating neuronal activities, including spike timing and firing pattern; however, the properties and functions of GABAA receptors at the axon are still poorly understood. By recording from the cut end (bleb) of the main axon trunk of layer -5 pyramidal neurons in prefrontal cortical slices, we found that currents evoked by GABA iontophoresis could be blocked by picrotoxin, indicating the expression of GABAA receptors in axons. Stationary noise analysis revealed that single-channel properties of axonal GABAA receptors were similar to those of somatic receptors. Perforated patch recording with gramicidin revealed that the reversal potential of the GABA response was more negative than the resting membrane potential at the axon trunk, suggesting that GABA may hyperpolarize the axonal membrane potential. Further experiments demonstrated that the activation of axonal GABAA receptors regulated the amplitude and duration of action potentials (APs) and decreased the AP-induced Ca2+ transients at the axon. Together, our results indicate that the waveform of axonal APs and the downstream Ca2+ signals are modulated by axonal GABAA receptors.
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Affiliation(s)
- Yang Xia
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China
| | - Yuan Zhao
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Mingpo Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China
| | - Shaoqun Zeng
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, P. R. China
- * E-mail: (YS); (SZ)
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, P. R. China
- * E-mail: (YS); (SZ)
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Qaddoumi MG, Ananthalakshmi KVV, Phillips OA, Edafiogho IO, Kombian SB. Evaluation of anticonvulsant actions of dibromophenyl enaminones using in vitro and in vivo seizure models. PLoS One 2014; 9:e99770. [PMID: 24945912 PMCID: PMC4063795 DOI: 10.1371/journal.pone.0099770] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/15/2014] [Indexed: 12/16/2022] Open
Abstract
Epilepsy and other seizure disorders are not adequately managed with currently available drugs. We recently synthesized a series of dibromophenyl enaminones and demonstrated that AK6 and E249 were equipotent to previous analogs but more efficacious in suppressing neuronal excitation. Here we examined the actions of these lead compounds on in vitro and in vivo seizure models. In vitro seizures were induced in the hippocampal slice chemically (zero Mg2+ buffer and picrotoxin) and electrically using patterned high frequency stimulation (HFS) of afferents. In vivo seizures were induced in rats using the 6 Hz and the maximal electroshock models. AK6 (10 µM) and E249 (10 µM) depressed the amplitude of population spikes recorded in area CA1 of the hippocampus by -50.5±4.3% and -40.1±3.1% respectively, with partial recovery after washout. In the zero Mg2+ model, AK6 (10 µM) depressed multiple population spiking (mPS) by -59.3±6.9% and spontaneous bursts (SBs) by -65.9±7.2% and in the picrotoxin-model by -43.3±7.2% and -50.0±8.3%, respectively. Likewise, E249 (10 µM) depressed the zero-Mg2+-induced mPS by -48.8±9.5% and SBs by -55.8±15.5%, and in the picrotoxin model by -37.1±5.5% and -56.5±11.4%, respectively. They both suppressed post-HFS induced afterdischarges and SBs. AK6 and E249 dose-dependently protected rats in maximal electroshock and 6 Hz models of in vivo seizures after 30 min pretreatment. Their level of protection in both models was similar to that obtained with phenytoin Finally, while AK6 had no effect on locomotion in rats, phenytoin significantly decreased locomotion. AK6 and E249, suppressed in vitro and in vivo seizures to a similar extent. Their in vivo activities are comparable with but not superior to phenytoin. The most efficacious, AK6 produced no locomotor suppression while phenytoin did. Thus, AK6 and E249 may be excellent candidates for further investigation as potential agents for the treatment of epilepsy syndromes with possibly less CNS side effects.
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Affiliation(s)
- Mohamed G. Qaddoumi
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
| | | | - Oludotun A. Phillips
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
| | - Ivan O. Edafiogho
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Saint Joseph, Hartford, Connecticut, United States of America
| | - Samuel B. Kombian
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
- * E-mail:
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Pezze M, McGarrity S, Mason R, Fone KC, Bast T. Too little and too much: hypoactivation and disinhibition of medial prefrontal cortex cause attentional deficits. J Neurosci 2014; 34:7931-46. [PMID: 24899715 PMCID: PMC4044251 DOI: 10.1523/jneurosci.3450-13.2014] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 04/11/2014] [Accepted: 04/24/2014] [Indexed: 12/21/2022] Open
Abstract
Attentional deficits are core symptoms of schizophrenia, contributing strongly to disability. Prefrontal dysfunction has emerged as a candidate mechanism, with clinical evidence for prefrontal hypoactivation and disinhibition (reduced GABAergic inhibition), possibly reflecting different patient subpopulations. Here, we tested in rats whether imbalanced prefrontal neural activity impairs attention. To induce prefrontal hypoactivation or disinhibition, we microinfused the GABA-A receptor agonist muscimol (C4H6N2O2; 62.5, 125, 250 ng/side) or antagonist picrotoxin (C30H34O13; 75, 150, 300 ng/side), respectively, into the medial prefrontal cortex. Using the five-choice serial reaction time (5CSRT) test, we showed that both muscimol and picrotoxin impaired attention (reduced accuracy, increased omissions). Muscimol also impaired response control (increased premature responses). In addition, muscimol dose dependently reduced open-field locomotor activity, whereas 300 ng of picrotoxin caused locomotor hyperactivity; sensorimotor gating (startle prepulse inhibition) was unaffected. Therefore, infusion effects on the 5CSRT test can be dissociated from sensorimotor effects. Combining microinfusions with in vivo electrophysiology, we showed that muscimol inhibited prefrontal firing, whereas picrotoxin increased firing, mainly within bursts. Muscimol reduced and picrotoxin enhanced bursting and both drugs changed the temporal pattern of bursting. Picrotoxin also markedly enhanced prefrontal LFP power. Therefore, prefrontal hypoactivation and disinhibition both cause attentional deficits. Considering the electrophysiological findings, this suggests that attention requires appropriately tuned prefrontal activity. Apart from attentional deficits, prefrontal disinhibition caused additional neurobehavioral changes that may be relevant to schizophrenia pathophysiology, including enhanced prefrontal bursting and locomotor hyperactivity, which have been linked to psychosis-related dopamine hyperfunction.
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Affiliation(s)
- Marie Pezze
- School of Psychology, Neuroscience@Nottingham, and
| | | | - Rob Mason
- Neuroscience@Nottingham, and School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Kevin C Fone
- Neuroscience@Nottingham, and School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Tobias Bast
- School of Psychology, Neuroscience@Nottingham, and
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Ho VM, Dallalzadeh LO, Karathanasis N, Keles MF, Vangala S, Grogan T, Poirazi P, Martin KC. GluA2 mRNA distribution and regulation by miR-124 in hippocampal neurons. Mol Cell Neurosci 2014; 61:1-12. [PMID: 24784359 DOI: 10.1016/j.mcn.2014.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 03/17/2014] [Accepted: 04/12/2014] [Indexed: 11/19/2022] Open
Abstract
AMPA-type glutamate receptors mediate fast, excitatory neurotransmission in the brain, and their concentrations at synapses are important determinants of synaptic strength. We investigated the post-transcriptional regulation of GluA2, the calcium-impermeable AMPA receptor subunit, by examining the subcellular distribution of its mRNA and evaluating its translational regulation by microRNA in cultured mouse hippocampal neurons. Using computational approaches, we identified a conserved microRNA-124 (miR-124) binding site in the 3'UTR of GluA2 and demonstrated that miR-124 regulated the translation of GluA2 mRNA reporters in a sequence-specific manner in luciferase assays. While we hypothesized that this regulation might occur in dendrites, our biochemical and fluorescent in situ hybridization (FISH) data indicate that GluA2 mRNA does not localize to dendrites or synapses of mouse hippocampal neurons. In contrast, we detected significant concentrations of miR-124 in dendrites. Overexpression of miR-124 in dissociated neurons results in a 30% knockdown of GluA2 protein, as measured by immunoblot and quantitative immunocytochemistry, without producing any changes in GluA2 mRNA concentrations. While total GluA2 concentrations are reduced, we did not detect any changes in the concentration of synaptic GluA2. We conclude from these results that miR-124 interacts with GluA2 mRNA in the cell body to downregulate translation. Our data support a model in which GluA2 is translated in the cell body and subsequently transported to neuronal dendrites and synapses, and suggest that synaptic GluA2 concentrations are modified primarily by regulated protein trafficking rather than by regulated local translation.
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Affiliation(s)
- Victoria M Ho
- Interdepartmental Program for Neuroscience, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA
| | - Liane O Dallalzadeh
- Interdepartmental Program for Neuroscience, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA
| | - Nestoras Karathanasis
- Department of Biology, University of Crete, Heraklion, Crete, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Mehmet F Keles
- Interdepartmental Program for Molecular, Cellular and Integrative Physiology, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA
| | - Sitaram Vangala
- Department of Medicine Statistics Core, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Tristan Grogan
- Department of Medicine Statistics Core, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Crete, Greece
| | - Kelsey C Martin
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA; Integrated Center for Learning and Memory, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1737, USA.
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Wu W, Yang Q, Fung KM, Humphreys MR, Brame LS, Cao A, Fang YT, Shih PT, Kropp BP, Lin HK. Linking γ-aminobutyric acid A receptor to epidermal growth factor receptor pathways activation in human prostate cancer. Mol Cell Endocrinol 2014; 383:69-79. [PMID: 24296312 DOI: 10.1016/j.mce.2013.11.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 10/25/2013] [Accepted: 11/21/2013] [Indexed: 11/26/2022]
Abstract
Neuroendocrine (NE) differentiation has been attributed to the progression of castration-resistant prostate cancer (CRPC). Growth factor pathways including the epidermal growth factor receptor (EGFR) signaling have been implicated in the development of NE features and progression to a castration-resistant phenotype. However, upstream molecules that regulate the growth factor pathway remain largely unknown. Using androgen-insensitive bone metastasis PC-3 cells and androgen-sensitive lymph node metastasis LNCaP cells derived from human prostate cancer (PCa) patients, we demonstrated that γ-aminobutyric acid A receptor (GABA(A)R) ligand (GABA) and agonist (isoguvacine) stimulate cell proliferation, enhance EGF family members expression, and activate EGFR and a downstream signaling molecule, Src, in both PC-3 and LNCaP cells. Inclusion of a GABA(A)R antagonist, picrotoxin, or an EGFR tyrosine kinase inhibitor, Gefitinib (ZD1839 or Iressa), blocked isoguvacine and GABA-stimulated cell growth, trans-phospohorylation of EGFR, and tyrosyl phosphorylation of Src in both PCa cell lines. Spatial distributions of GABAAR α₁ and phosphorylated Src (Tyr416) were studied in human prostate tissues by immunohistochemistry. In contrast to extremely low or absence of GABA(A)R α₁-positive immunoreactivity in normal prostate epithelium, elevated GABA(A)R α₁ immunoreactivity was detected in prostate carcinomatous glands. Similarly, immunoreactivity of phospho-Src (Tyr416) was specifically localized and limited to the nucleoli of all invasive prostate carcinoma cells, but negative in normal tissues. Strong GABAAR α₁ immunoreactivity was spatially adjacent to the neoplastic glands where strong phospho-Src (Tyr416)-positive immunoreactivity was demonstrated, but not in adjacent to normal glands. These results suggest that the GABA signaling is linked to the EGFR pathway and may work through autocrine or paracine mechanism to promote CRPC progression.
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Affiliation(s)
- Weijuan Wu
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Qing Yang
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Kar-Ming Fung
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
| | | | - Lacy S Brame
- Department of Psychology, University of Oklahoma, Norman, OK 73019, USA
| | - Amy Cao
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Yu-Ting Fang
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Food Science, National Pingtung University of Science and Technology, Pingtung 91207, Taiwan, ROC
| | - Pin-Tsen Shih
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Food Science, National Pingtung University of Science and Technology, Pingtung 91207, Taiwan, ROC
| | - Bradley P Kropp
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Hsueh-Kung Lin
- Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Ledri M, Madsen MG, Nikitidou L, Kirik D, Kokaia M. Global optogenetic activation of inhibitory interneurons during epileptiform activity. J Neurosci 2014; 34:3364-77. [PMID: 24573293 PMCID: PMC6795301 DOI: 10.1523/jneurosci.2734-13.2014] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 01/06/2014] [Accepted: 01/27/2014] [Indexed: 11/21/2022] Open
Abstract
Optogenetic techniques provide powerful tools for bidirectional control of neuronal activity and investigating alterations occurring in excitability disorders, such as epilepsy. In particular, the possibility to specifically activate by light-determined interneuron populations expressing channelrhodopsin-2 provides an unprecedented opportunity of exploring their contribution to physiological and pathological network activity. There are several subclasses of interneurons in cortical areas with different functional connectivity to the principal neurons (e.g., targeting their perisomatic or dendritic compartments). Therefore, one could optogenetically activate specific or a mixed population of interneurons and dissect their selective or concerted inhibitory action on principal cells. We chose to explore a conceptually novel strategy involving simultaneous activation of mixed populations of interneurons by optogenetics and study their impact on ongoing epileptiform activity in mouse acute hippocampal slices. Here we demonstrate that such approach results in a brief initial action potential discharge in CA3 pyramidal neurons, followed by prolonged suppression of ongoing epileptiform activity during light exposure. Such sequence of events was caused by massive light-induced release of GABA from ChR2-expressing interneurons. The inhibition of epileptiform activity was less pronounced if only parvalbumin- or somatostatin-expressing interneurons were activated by light. Our data suggest that global optogenetic activation of mixed interneuron populations is a more effective approach for development of novel therapeutic strategies for epilepsy, but the initial action potential generation in principal neurons needs to be taken in consideration.
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Affiliation(s)
- Marco Ledri
- Experimental Epilepsy Group, Epilepsy Center, Department of Clinical Sciences, Lund University Hospital, 22184 Lund, Sweden, and
| | - Marita Grønning Madsen
- Experimental Epilepsy Group, Epilepsy Center, Department of Clinical Sciences, Lund University Hospital, 22184 Lund, Sweden, and
| | - Litsa Nikitidou
- Experimental Epilepsy Group, Epilepsy Center, Department of Clinical Sciences, Lund University Hospital, 22184 Lund, Sweden, and
| | - Deniz Kirik
- Brain Repair and Imaging in Neural Systems (BRAINS) Unit, Department of Experimental Medical Sciences, Lund University Hospital, 22184 Lund, Sweden
| | - Merab Kokaia
- Experimental Epilepsy Group, Epilepsy Center, Department of Clinical Sciences, Lund University Hospital, 22184 Lund, Sweden, and
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Martella G, Maltese M, Nisticò R, Schirinzi T, Madeo G, Sciamanna G, Ponterio G, Tassone A, Mandolesi G, Vanni V, Pignatelli M, Bonsi P, Pisani A. Regional specificity of synaptic plasticity deficits in a knock-in mouse model of DYT1 dystonia. Neurobiol Dis 2014; 65:124-32. [PMID: 24503369 DOI: 10.1016/j.nbd.2014.01.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 01/24/2014] [Indexed: 01/07/2023] Open
Abstract
DYT1 dystonia is a movement disorder caused by a deletion in the C-terminal of the protein torsinA. It is unclear how torsinA mutation might disrupt cellular processes encoding motor activity, and whether this impairment occurs in specific brain regions. Here, we report a selective impairment of corticostriatal synaptic plasticity in knock-in mice heterozygous for Δ-torsinA (Tor1a(+/Δgag) mice) as compared to controls (Tor1a(+/+) mice). In striatal spiny neurons from Tor1a(+/Δgag) mice, high-frequency stimulation failed to induce long-term depression (LTD), whereas long-term potentiation (LTP) exhibited increased amplitude. Of interest, blockade of D2 dopamine receptors (D2Rs) increased LTP in Tor1a(+/+) mice to a level comparable to that measured in Tor1a(+/Δgag) mice and normalized the levels of potentiation across mouse groups. A low-frequency stimulation (LFS) protocol was unable to depotentiate corticostriatal synapses in Tor1a(+/Δgag) mice. Muscarinic M1 acetylcholine receptor (mAChR) blockade rescued plasticity deficits. Additionally, we found an abnormal responsiveness of cholinergic interneurons to D2R activation, consisting in an excitatory response rather than the expected inhibition, further confirming an imbalance between dopaminergic and cholinergic signaling in the striatum. Conversely, synaptic activity and plasticity in the CA1 hippocampal region were unaltered in Tor1a(+/Δgag) mice. Importantly, the M1 mAChR-dependent enhancement of hippocampal LTP was unaffected in both genotypes. Similarly, both basic properties of dopaminergic nigral neurons and their responses to D2R activation were normal. These results provide evidence for a regional specificity of the electrophysiological abnormalities observed and demonstrate the reproducibility of such alterations in distinct models of DYT1 dystonia.
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Affiliation(s)
- G Martella
- Department of System Medicine, University of Rome "Tor Vergata", Italy; Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - M Maltese
- Department of System Medicine, University of Rome "Tor Vergata", Italy
| | - R Nisticò
- Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy; Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Italy
| | - T Schirinzi
- Department of System Medicine, University of Rome "Tor Vergata", Italy
| | - G Madeo
- Department of System Medicine, University of Rome "Tor Vergata", Italy
| | - G Sciamanna
- Department of System Medicine, University of Rome "Tor Vergata", Italy; Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - G Ponterio
- Department of System Medicine, University of Rome "Tor Vergata", Italy; Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - A Tassone
- Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - G Mandolesi
- Department of System Medicine, University of Rome "Tor Vergata", Italy; Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - V Vanni
- Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - M Pignatelli
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Italy
| | - P Bonsi
- Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy
| | - A Pisani
- Department of System Medicine, University of Rome "Tor Vergata", Italy; Laboratory of Neurophysiology and Synaptic Plasticity, IRCCS Fondazione Santa Lucia, Rome, Italy.
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Heredia L, Torrente M, Colomina MT, Domingo JL. Assessing anxiety in C57BL/6J mice: a pharmacological characterization of the open-field and light/dark tests. J Pharmacol Toxicol Methods 2013; 69:108-14. [PMID: 24374104 DOI: 10.1016/j.vascn.2013.12.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/16/2013] [Accepted: 12/16/2013] [Indexed: 01/02/2023]
Abstract
INTRODUCTION In order to assess anxiety in mammals various tests and species are currently available. These current assays measure changes in anxiety-like behaviors. The open-field and the light/dark are anxiety tests based on the spontaneous behavior of the animals, with C57BL/6J mice being a frequently used strain in behavioral studies. However, the suitability of this strain as a choice in anxiety studies has been questioned. In this study, we performed two pharmacological characterizations of this strain in both the open-field and the light/dark tests. METHODS We examined the changes in the anxiety-like behaviors of C57BL/6J mice exposed to chlordiazepoxide (CDP), an anxiolytic drug, at doses of 5 and 10 mg/kg, picrotoxine (PTX), an anxiogenic drug, at doses of 0.5 and 1 mg/kg, and methylphenidate (MPH), a psychomotor stimulant drug, at doses of 5 and 10 mg/kg, in a first experiment. In a second experiment, we tested CDP at 2.5 mg/kg, PTX at 2 mg/kg and MPH at 2.5 mg/kg. RESULTS Results showed an absence of anxiolytic-like effects of CDP in open-field and light/dark tests. Light/dark test was more sensitive to the anxiogenic effects of PTX than the open-field test. Finally, a clear anxiogenic effect of MPH was observed in the two tests. DISCUSSION Although C57BL/6J mice could not be a sensitive model to study anxiolytic effects in pharmacological or behavioral interventions, it might be a suitable model to test anxiogenic effects. Further studies are necessary to corroborate these results.
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Affiliation(s)
- Luis Heredia
- CRAMC (Research Center for Behavior Assessment), Department of Psychology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain.
| | - Margarita Torrente
- CRAMC (Research Center for Behavior Assessment), Department of Psychology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain.
| | - María T Colomina
- CRAMC (Research Center for Behavior Assessment), Department of Psychology, Universitat Rovira i Virgili, 43007 Tarragona, Spain; Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain.
| | - José L Domingo
- Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, 43201 Reus, Spain.
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Wang K, Long Q, Jia C, Liu Y, Yi X, Yang H, Fei Z, Liu W. Over-expression of Mash1 improves the GABAergic differentiation of bone marrow mesenchymal stem cells in vitro. Brain Res Bull 2013; 99:84-94. [PMID: 24144723 DOI: 10.1016/j.brainresbull.2013.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 10/08/2013] [Accepted: 10/10/2013] [Indexed: 01/11/2023]
Abstract
Bone marrow mesenchymal stem cells (BMSCs) have been shown to be a promising cell type for the study of neuronal differentiation; however, few attempts had been made to differentiate these cells into inhibitory gamma-aminobutyric acid (GABA)ergic neurons. In this study, we over-expressed mammalian achaete-scute homologue-1 (Mash1), a basic helix-loop-helix (bHLH) transcription factor, in Sprague-Dawley rat BMSCs via lentiviral vectors, and then induced neuronal differentiation of these cells using conditioned medium. Our Western blot results show that, under conditions of differentiation, Mash1-overexpressing BMSCs exhibit an increased expression of neuronal markers and a greater degree of neuronal morphology compared to control, non-Mash1-overexpressing cells. Using immunocytochemistry, we observed increased expression of glutamic acid decarboxylase 67 (GAD67), as well as neuron-specific nuclear protein (NeuN) and β3-tubulin, in Mash1-overexpressing BMSCs compared to control cells. Moreover, we also found the differentiated cells showed representative traces of action potentials in electrophysiological characterization. In conclusion, our study demonstrated that over-expression of Mash1 can improve GABAergic differentiation of BMSCs in vitro.
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Affiliation(s)
- Kai Wang
- Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Fourth Military Medical University, No.17 Chang-le West Road, Xi'an 710032, China; Department of Neurosurgery, Qingdao 401 Hospital of PLA, No. 22 Minjiang Road, Qingdao 266071, China
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Kusek M, Tokarski K, Hess G. Repeated restraint stress enhances glutamatergic transmission in the paraventricular nucleus of the rat hypothalamus. J Physiol Pharmacol 2013; 64:565-570. [PMID: 24304570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 10/28/2013] [Indexed: 06/02/2023]
Abstract
Corticotropin-releasing hormone (CRH)-synthesizing parvocellular neuroendocrine neurons of the hypothalamic paraventricular nucleus (PVN) play a key role in the activation of the hypothalamic-pituitary-adrenal axis (HPA). It is well known that excitatory and inhibitory inputs that regulate the activity of these neurons may undergo stress-related modifications; however, the effect of repeated restraint stress on the function of glutamatergic and GABAergic synapses on PVN parvocellular neuroendocrine neurons has not been fully understood so far. Adolescent male Wistar rats were subjected to restraint lasting 10 min and repeated twice daily for 3 days. Brain slices were prepared 24 hours after the last restraint session and were studied ex vivo. Whole-cell patch-clamping was used to record spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) from parvocellular neuroendocrine neurons of the PVN. Repeated restraint stress resulted in an increase in the mean frequency of sEPSCs and in a decrease in the rise time and the decay time constant of sEPSCs. There was no change in the mean amplitude of sEPSCs. The parameters characterizing sIPSCs also remained unaltered. In addition, the injected current vs. spiking rate ratio of parvocellular neurons was decreased. In conclusion, restraint stress, repeated for 3 days, selectively enhances excitatory synaptic inputs to parvocellular neurons of the PVN, these modifications being accompanied with a decrease in the intrinsic excitability of PVN neuroendocrine parvocellular neurons.
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Affiliation(s)
- M Kusek
- Department of Physiology, Institute of Pharmacology, Polish Academy of Sciences, Cracow, Poland.
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Abstract
Sensory systems change their sensitivity based on recent stimuli to adjust their response range to the range of inputs and to predict future sensory input. Here, we report the presence of retinal ganglion cells that have antagonistic plasticity, showing central adaptation and peripheral sensitization. Ganglion cell responses were captured by a spatiotemporal model with independently adapting excitatory and inhibitory subunits, and sensitization requires GABAergic inhibition. Using a simple theory of signal detection, we show that the sensitizing surround conforms to an optimal inference model that continually updates the prior signal probability. This indicates that small receptive field regions have dual functionality--to adapt to the local range of signals but sensitize based upon the probability of the presence of that signal. Within this framework, we show that sensitization predicts the location of a nearby object, revealing prediction as a functional role for adapting inhibition in the nervous system.
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Affiliation(s)
- David B. Kastner
- Neuroscience Program, Stanford University School of Medicine, 299 Campus Drive W., Stanford, CA, USA
| | - Stephen A. Baccus
- Department of Neurobiology, Stanford University School of Medicine, 299 Campus Drive W., Stanford, CA, USA
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