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Hannan SB, Penzinger R, Mickute G, Smart TG. CGP7930 - An allosteric modulator of GABA BRs, GABA ARs and inwardly-rectifying potassium channels. Neuropharmacology 2023; 238:109644. [PMID: 37422181 PMCID: PMC10951960 DOI: 10.1016/j.neuropharm.2023.109644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/01/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023]
Abstract
Type-A and -B GABA receptors (GABAARs/GABABRs) control brain function and behaviour by fine tuning neurotransmission. Over-time these receptors have become important therapeutic targets for treating neurodevelopmental and neuropsychiatric disorders. Several positive allosteric modulators (PAMs) of GABARs have reached the clinic and selective targeting of receptor subtypes is crucial. For GABABRs, CGP7930 is a widely used PAM for in vivo studies, but its full pharmacological profile has not yet been established. Here, we reveal that CGP7930 has multiple effects not only on GABABRs but also GABAARs, which for the latter involves potentiation of GABA currents, direct receptor activation, and also inhibition. Furthermore, at higher concentrations, CGP7930 also blocks G protein-coupled inwardly-rectifying K+ (GIRK) channels diminishing GABABR signalling in HEK 293 cells. In male and female rat hippocampal neuron cultures, CGP7930 allosteric effects on GABAARs caused prolonged rise and decay times and reduced the frequency of inhibitory postsynaptic currents and potentiated GABAAR-mediated tonic inhibition. Additional comparison between predominant synaptic- and extrasynaptic-isoforms of GABAAR indicated no evident subtype selectivity for CGP7930. In conclusion, our study of CGP7930 modulation of GABAARs, GABABRs and GIRK channels, indicates this compound is unsuitable for use as a specific GABABR PAM.
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Affiliation(s)
- Saad B Hannan
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Reka Penzinger
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Ginte Mickute
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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Keeping the Balance: GABAB Receptors in the Developing Brain and Beyond. Brain Sci 2022; 12:brainsci12040419. [PMID: 35447949 PMCID: PMC9031223 DOI: 10.3390/brainsci12040419] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 12/16/2022] Open
Abstract
The main neurotransmitter in the brain responsible for the inhibition of neuronal activity is γ-aminobutyric acid (GABA). It plays a crucial role in circuit formation during development, both via its primary effects as a neurotransmitter and also as a trophic factor. The GABAB receptors (GABABRs) are G protein-coupled metabotropic receptors; on one hand, they can influence proliferation and migration; and, on the other, they can inhibit cells by modulating the function of K+ and Ca2+ channels, doing so on a slower time scale and with a longer-lasting effect compared to ionotropic GABAA receptors. GABABRs are expressed pre- and post-synaptically, at both glutamatergic and GABAergic terminals, thus being able to shape neuronal activity, plasticity, and the balance between excitatory and inhibitory synaptic transmission in response to varying levels of extracellular GABA concentration. Furthermore, given their subunit composition and their ability to form complexes with several associated proteins, GABABRs display heterogeneity with regard to their function, which makes them a promising target for pharmacological interventions. This review will describe (i) the latest results concerning GABABRs/GABABR-complex structures, their function, and the developmental time course of their appearance and functional integration in the brain, (ii) their involvement in manifestation of various pathophysiological conditions, and (iii) the current status of preclinical and clinical studies involving GABABR-targeting drugs.
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Γ-Aminobutyric acid in adult brain: an update. Behav Brain Res 2019; 376:112224. [DOI: 10.1016/j.bbr.2019.112224] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/09/2019] [Accepted: 09/09/2019] [Indexed: 01/21/2023]
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Membrane action of polyhexamethylene guanidine hydrochloride revealed on smooth muscle cells, nerve tissue and rat blood platelets: A biocide driven pore-formation in phospholipid bilayers. Toxicol In Vitro 2019; 60:389-399. [PMID: 31195087 DOI: 10.1016/j.tiv.2019.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/08/2019] [Accepted: 06/09/2019] [Indexed: 12/31/2022]
Abstract
A well-known cationic biocide of guanidine polymer family, polyhexamethylene guanidine hydrochloride (PHMG) has been tested against smooth muscle cells isolated from swine myometrium, synaptosomes of rat brain nerve terminals and rat blood platelets for the membrane action. It was established that PHMG blocked the activity of Na+,K+-ATPase of smooth muscle cells plasma membrane by 82.2 ± 0.9% at a concentration of 7 ppm, whilst a dose-dependent depolarization of synaptosomes and platelets became appreciable at 100-500 ppm. Comparative studies by the methods of mass spectrometry (MALDI-TOF and PDMS-TOF), viscosimetry, dynamic light scattering and model phospholipid membranes revealed PHMG oligomers with various number of repeat units (8-16) that formed K+-selective potential-dependent pores in sterol-free phosphatidylethanolamine-containing phospholipid bilayers at a concentration of 1 ppm. Obtained results suggest that besides acidic lipids and membrane proteins phosphatidylethanolamine and cholesterol are the other major factors responsible for the differences between PHMG-induced plasma membrane depolarization of microbial and eukaryotic cells and thus, diverse modes of PHMG membrane action.
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Lee HS, Seo C, Kim YA, Park M, Choi B, Ji M, Lee S, Paik MJ. Metabolomic study of polyamines in rat urine following intraperitoneal injection of γ-hydroxybutyric acid. Metabolomics 2019; 15:58. [PMID: 30941522 DOI: 10.1007/s11306-019-1517-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Recently, illegal abuse of γ-hydroxybutyric acid (GHB) has increased in drug-facilitated crimes, but the determination of GHB exposure and intoxication is difficult due to rapid metabolism of GHB. Its biochemical mechanism has not been completely investigated. And a metabolomic study by polyamine profile and pattern analyses was not performed in rat urine following intraperitoneal injection with GHB. OBJECTIVES Urinary polyamine (PA) profiling by gas chromatography-tandem mass spectrometry was performed to monitor an altered PA according to GHB administration. METHODS Polyamine profiling analysis by gas chromatography-mass spectrometry combined with star pattern recognition analysis was performed in this study. The multivariate statistical analysis was used to evaluate discrimination among control and GHB administration groups. RESULTS Six polyamines were determined in control, single and multiple GHB administration groups. Star pattern showed distorted hexagonal shapes with characteristic and readily distinguishable patterns for each group. N1-Acetylspermine (p < 0.001), putrescine (p < 0.006), N1-acetylspermidine (p < 0.009), and spermine (p < 0.027) were significantly increased in single administration group but were significantly lower in the multiple administration group than in the control group. N1-Acetylspermine was the main polyamine for discrimination among control, single and multiple administration groups. Spermine showed similar levels in single and multiple administration groups. CONCLUSIONS The polyamine metabolic pattern was monitored in GHB administration groups. N1-Acetylspermine and spermine were evaluated as potential biomarkers of GHB exposure and addiction.
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Affiliation(s)
- Hyeon-Seong Lee
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea
| | - Chan Seo
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea
| | - Young-A Kim
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea
| | - Meejung Park
- National Forensic Service, 10 Ipchoon-ro, Wonju, Kangwon-do, 220-170, Republic of Korea
| | - Boyeon Choi
- College of Pharmacy, Keimyung University, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 704-701, Republic of Korea
| | - Moongi Ji
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea
| | - Sooyeun Lee
- College of Pharmacy, Keimyung University, 1095 Dalgubeol-daero, Dalseo-gu, Daegu, 704-701, Republic of Korea.
| | - Man-Jeong Paik
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 540-950, Republic of Korea.
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Elucidation of the neural circuits activated by a GABA B receptor positive modulator: Relevance to anxiety. Neuropharmacology 2017; 136:129-145. [PMID: 28734870 DOI: 10.1016/j.neuropharm.2017.07.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 01/09/2023]
Abstract
Although there is much evidence for a role of GABAB receptors in the pathophysiology of anxiety, the underlying neuronal mechanisms are largely unclear. The GABAB receptor allosteric positive modulator, GS39783, exerts anxiolytic effects without interfering with GABAB-mediated modulation of body temperature, cognitive performance and locomotor activity thus offering advantages over GABAB receptor agonists. However, the precise neural circuits underlying the anxiolytic effects of GS39783 are unknown. The aim of the present study was to identify brain structures and associated neuronal circuits that are modulated by GS39783 under either basal or mild stress conditions. To this end, the expression pattern of c-Fos, a marker of neuronal activation, was examined in mice acutely treated with GS39783 under basal conditions or following a mild anxiogenic challenge induced by exposure to the Open Arm (OA) of an Elevated Plus Maze. OA exposure enhanced c-Fos expression in vehicle-treated animals in several brain regions, including the medial prefrontal cortex, lateral septum, amygdala, hippocampus, paraventricular nucleus of the hypothalamus and the periaqueductal gray (PAG). Under basal conditions, GS39783 increased c-Fos in a restricted panel of areas notably amygdala nuclei, cortical areas and PAG subregions, while it inhibited c-Fos expression in the dorsal raphe nucleus (DRN). Under stress conditions, GS39783 reversed OA-induced c-Fos expression in the granular cell layer of the dentate gyrus, no longer increased c-Fos expression in the amygdala nor reduced c-Fos expression in the DRN. These specific patterns of neural activation by GS39783 might explain the neurobiological correlates implicated in GABAB-mediated anti-anxiety effects. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Korpi ER, Linden AM, Hytönen HR, Paasikoski N, Vashchinkina E, Dudek M, Herr DR, Hyytiä P. Continuous delivery of naltrexone and nalmefene leads to tolerance in reducing alcohol drinking and to supersensitivity of brain opioid receptors. Addict Biol 2017; 22:1022-1035. [PMID: 26990998 DOI: 10.1111/adb.12393] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/21/2016] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
Abstract
Opioid antagonist treatments reduce alcohol drinking in rodent models and in alcohol-dependent patients, with variable efficacy across different studies. These treatments may suffer from the development of tolerance and opioid receptor supersensitivity, as suggested by preclinical models showing activation of these processes during and after subchronic high-dose administration of the short-acting opioid antagonist naloxone. In the present study, we compared equipotent low and moderate daily doses of naltrexone and nalmefene, two opioid antagonists in the clinical practice for treatment of alcoholism. The antagonists were given here subcutaneously for 7 days either as daily injections or continuous osmotic minipump-driven infusions to alcohol-preferring AA rats having trained to drink 10% alcohol in a limited access protocol. One day after stopping the antagonist treatment, [35 S]GTPγS autoradiography on brain cryostat sections was carried out to examine the coupling of receptors to G protein activation. The results prove the efficacy of repeated injections over infused opioid antagonists in reducing alcohol drinking. Tolerance to the reducing effect on alcohol drinking and to the enhancement of G protein coupling to μ-opioid receptors in various brain regions were consistently detected only after infused antagonists. Supersensitivity of κ-opioid receptors was seen in the ventral and dorsal striatal regions especially by infused nalmefene. Nalmefene showed no clear agonistic activity in rat brain sections or at human recombinant κ-opioid receptors. The findings support the as-needed dosing practice, rather than the standard continual dosing, in the treatment of alcoholism with opioid receptor antagonists.
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Affiliation(s)
- Esa R. Korpi
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
- Department of Pharmacology, Yong Loo Lin School of Medicine; National University of Singapore; Singapore
| | - Anni-Maija Linden
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
| | - Heidi R. Hytönen
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
| | - Nelli Paasikoski
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
| | - Elena Vashchinkina
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
| | - Mateusz Dudek
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
| | - Deron R. Herr
- Department of Pharmacology, Yong Loo Lin School of Medicine; National University of Singapore; Singapore
| | - Petri Hyytiä
- Department of Pharmacology, Faculty of Medicine; University of Helsinki; Finland
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Borisova T, Dekaliuk M, Pozdnyakova N, Pastukhov A, Dudarenko M, Borysov A, Vari SG, Demchenko AP. Harmful impact on presynaptic glutamate and GABA transport by carbon dots synthesized from sulfur-containing carbohydrate precursor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:17688-17700. [PMID: 28601995 DOI: 10.1007/s11356-017-9414-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 05/30/2017] [Indexed: 04/16/2023]
Abstract
Carbon nanoparticles that may be potent air pollutants with adverse effects on human health often contain heteroatoms including sulfur. In order to study in detail their effects on different physiological and biochemical processes, artificially produced carbon dots (CDs) with well-controlled composition that allows fluorescence detection may be of great use. Having been prepared from different types of organic precursors, CDs expose different atoms at their surface suggesting a broad variation of functional groups. Recently, we demonstrated neurotoxic properties of CDs synthesized from the amino acid β-alanine, and it is of importance to analyze whether CDs obtained from different precursors and particularly those exposing sulfur atoms induce similar neurotoxic effects. This study focused on synthesis of CDs from the sulfur-containing precursor thiourea-CDs (TU-CDs) with a size less than 10 nm, their characterization, and neuroactivity assessment. Neuroactive properties of TU-CDs were analyzed based on their effects on the key characteristics of glutamatergic and γ-aminobutyric acid (GABA) neurotransmission in isolated rat brain nerve terminals. It was observed that TU-CDs (0.5-1.0 mg/ml) attenuated the initial velocity of Na+-dependent transporter-mediated uptake and accumulation of L-[14C]glutamate and [3H]GABA by nerve terminals in a dose-dependent manner and increased the ambient level of the neurotransmitters. Starting from the concentration of 0.2 mg/ml, TU-CDs evoked a gradual dose-dependent depolarization of the plasma membrane of nerve terminals measured with the cationic potentiometric dye rhodamine 6G. Within the concentration range of 0.1-0.5 mg/ml, TU-CDs caused an "unphysiological" step-like increase in fluorescence intensity of the рН-sensitive fluorescent dye acridine orange accumulated by synaptic vesicles. Therefore, despite different surface properties and fluorescent features of CDs prepared from different starting materials (thiourea and β-alanine), their principal neurotoxic effects are analogous but displayed at a different level of efficiency. Sulfur-containing TU-CDs exhibit lower effects (by ~30%) on glutamate and GABA transport in the nerve terminals in comparison with sulfur-free β-alanine CDs. Our results suggest considering that an uncontrolled presence of carbon-containing particulate matter in the human environment may pose a toxicity risk for the central nervous system.
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Affiliation(s)
- Tatiana Borisova
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine.
| | - Mariia Dekaliuk
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine
| | - Natalia Pozdnyakova
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine
| | - Artem Pastukhov
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine
| | - Marina Dudarenko
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine
| | - Arsenii Borysov
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine
| | - Sandor G Vari
- International Research and Innovation in Medicine Program, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alexander P Demchenko
- Dept. Neurochemistry and Lab. of Nanobiotechnologies Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Street, Kiev, 01601, Ukraine
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Morse BL, Chadha GS, Felmlee MA, Follman KE, Morris ME. Effect of chronic γ-hydroxybutyrate (GHB) administration on GHB toxicokinetics and GHB-induced respiratory depression. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2017; 43:686-693. [PMID: 28662343 DOI: 10.1080/00952990.2017.1339055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND γ-hydroxybutyrate (GHB) has a high potential for illicit use; overdose of this compound results in sedation, respiratory depression and death. Tolerance to the hypnotic/sedative and electroencephalogram effects of GHB occurs with chronic GHB administration; however, tolerance to respiratory depression has not been evaluated. GHB toxicodynamic effects are mediated predominantly by GABAB receptors. Chronic treatment may affect monocarboxylate transporters (MCTs) and alter the absorption, renal clearance and brain uptake of GHB. OBJECTIVES To determine effects of chronic GHB dosing on GHB toxicokinetics, GHB-induced respiratory depression, and MCT expression. METHODS Rats were administered GHB 600 mg/kg intravenously daily for 5 days. Plasma, urine and tissue samples and respiratory measurements were obtained on days 1 and 5. Plasma and urine were analyzed for GHB by LC/MS/MS and tissue samples for expression of MCT1, 2 and 4 and their accessory proteins by QRT-PCR. RESULTS No differences in GHB pharmacokinetics or respiratory depression were observed between days 1 and 5. Opposing changes in MCT1 and MCT4 mRNA expression were observed in kidney samples on day 5 compared to GHB-naïve animals, and MCT4 expression was increased in the intestine. CONCLUSIONS The lack of tolerance observed with GHB-induced respiratory depression, in contrast to the tolerance reported for the sedative/hypnotic and electroencephalogram effects, suggests that different GABAB receptor subtypes may be involved in different GABAB-mediated toxicodynamic effects of GHB. Chronic or binge users of GHB may be at no less risk for fatality from respiratory arrest with a GHB overdose than with a single dose of GHB.
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Affiliation(s)
- Bridget L Morse
- a Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences , University at Buffalo, State University of New York , Buffalo , NY , USA.,b Investigative Drug Disposition, Transporters & Pharmacogenomics , Eli Lilly and Company , Indianapolis , IN , USA
| | - Gurkishan S Chadha
- a Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences , University at Buffalo, State University of New York , Buffalo , NY , USA.,c School of Pharmacy , University of New England , Biddeford , ME , USA
| | - Melanie A Felmlee
- a Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences , University at Buffalo, State University of New York , Buffalo , NY , USA.,d Department of Pharmaceutics & Medicinal Chemistry, Thomas J. Long School of Pharmacy & Health Sciences , University of the Pacific , Stockton , CA , USA
| | - Kristin E Follman
- a Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences , University at Buffalo, State University of New York , Buffalo , NY , USA
| | - Marilyn E Morris
- a Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences , University at Buffalo, State University of New York , Buffalo , NY , USA
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10
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Li M, Milligan CJ, Wang H, Walker A, Churilov L, Lawrence AJ, Reid CA, Hopkins SC, Petrou S. KCTD12 modulation of GABA(B) receptor function. Pharmacol Res Perspect 2017; 5:e00319. [PMID: 28713569 PMCID: PMC5508304 DOI: 10.1002/prp2.319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/21/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
Abstract
The molecular composition and functional diversity of native GABAB receptors (GABABR) are still poorly understood, thus hindering development of selective GABABR ligands. Potassium channel tetramerization domain‐containing protein (KCTD) 12 is a GABABR auxiliary subunit and mouse KCTD12 can alter GABABR function. In this study, we sought to characterize the effects of human KCTD12 on GABABR kinetics and pharmacology, using an automated electrophysiological assay. Seizure susceptibility and ethanol consumption were also investigated in a KCTD12 knockout mouse model. Human KCTD12 co‐expression altered the kinetics of GABABR‐mediated GIRK channels, speeding rates of both activation and desensitization. Analysis of concentration‐response curves showed that KCTD12 coexpression did not alter effects of the agonists GABA or baclofen on GABABR. KCTD12 coexpression enhanced the potentiating effects of the positive allosteric modulator CGP7930, and its effects on GABABR activation and desensitization. The function of KCTD12 in vivo was examined, using the KCTD12 knockout mouse model. The knockout mice were more resistant to a pentylenetetrazole proconvulsant challenge suggesting reduced seizure susceptibility. In the two bottle preference test, KCTD12 knockout mice demonstrated a reduced consumption at high ethanol concentrations. In summary, human KCTD12 accelerated the kinetics of GABABR in vitro, in a manner possibly sensitive to allosteric pharmacological modulation. This study also provides novel in vivo evidence that the interaction between KCTD12 and GABABR is of physiological significance, and may be a mechanism to more selectively modulate GABABR.
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Affiliation(s)
- Melody Li
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Carol J Milligan
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Haiyan Wang
- Sunovion Pharmaceuticals Inc Marlborough Massachusetts
| | - Andrew Walker
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Leonid Churilov
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | | | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia.,Department of Anatomy and Neuroscience University of Melbourne Parkville Victoria Australia.,Centre for Neural Engineering University of Melbourne Parkville Victoria Australia
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11
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Kamal RM, van Noorden MS, Franzek E, Dijkstra BAG, Loonen AJM, De Jong CAJ. The Neurobiological Mechanisms of Gamma-Hydroxybutyrate Dependence and Withdrawal and Their Clinical Relevance: A Review. Neuropsychobiology 2016; 73:65-80. [PMID: 27003176 DOI: 10.1159/000443173] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 11/29/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVE x03B3;-Hydroxybutyrate (GHB) has gained popularity as a drug of abuse. In the Netherlands the number of patients in treatment for GHB dependence has increased sharply. Clinical presentation of GHB withdrawal can be life threatening. We aim, through this overview, to explore the neurobiological pathways causing GHB dependency and withdrawal, and their implications for treatment choices. METHODS In this work we review the literature discussing the findings from animal models to clinical studies focused on the neurobiological pathways of endogenous but mainly exogenous GHB. RESULTS Chronic abuse of GHB exerts multifarious neurotransmitter and neuromodulator effects on x03B3;-aminobutyric acid (GABA), glutamate, dopamine, serotonin, norepinephrine and cholinergic systems. Moreover, important effects on neurosteroidogenesis and oxytocin release are wielded. GHB acts mainly via a bidirectional effect on GABAB receptors (GABABR; subunits GABAB1 and GABAB2), depending on the subunit of the GIRK (G-protein-dependent ion inwardly rectifying potassium) channel involved, and an indirect effect of the cortical and limbic inputs outside the nucleus accumbens. GHB also activates a specific GHB receptor and β1-subunits of α4-GABAAR. Reversing this complex interaction of neurobiological mechanisms by the abrupt cessation of GHB use results in a withdrawal syndrome with a diversity of symptoms of different intensity, depending on the pattern of GHB abuse. CONCLUSION The GHB withdrawal symptoms cannot be related to a single mechanism or neurological pathway, which implies that different medication combinations are needed for treatment. A single drug class, such as benzodiazepines, gabapentin or antipsychotics, is unlikely to be sufficient to avoid life-threatening complications. Detoxification by means of titration and tapering of pharmaceutical GHB can be considered as a promising treatment that could make polypharmacy redundant.
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Affiliation(s)
- Rama M Kamal
- Nijmegen Institute for Scientist-Practitioners in Addiction (NISPA), Nijmegen, The Netherlands
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12
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Konczal M, Koteja P, Orlowska-Feuer P, Radwan J, Sadowska ET, Babik W. Genomic Response to Selection for Predatory Behavior in a Mammalian Model of Adaptive Radiation. Mol Biol Evol 2016; 33:2429-40. [PMID: 27401229 DOI: 10.1093/molbev/msw121] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
If genetic architectures of various quantitative traits are similar, as studies on model organisms suggest, comparable selection pressures should produce similar molecular patterns for various traits. To test this prediction, we used a laboratory model of vertebrate adaptive radiation to investigate the genetic basis of the response to selection for predatory behavior and compare it with evolution of aerobic capacity reported in an earlier work. After 13 generations of selection, the proportion of bank voles (Myodes [=Clethrionomys] glareolus) showing predatory behavior was five times higher in selected lines than in controls. We analyzed the hippocampus and liver transcriptomes and found repeatable changes in allele frequencies and gene expression. Genes with the largest differences between predatory and control lines are associated with hunger, aggression, biological rhythms, and functioning of the nervous system. Evolution of predatory behavior could be meaningfully compared with evolution of high aerobic capacity, because the experiments and analyses were performed in the same methodological framework. The number of genes that changed expression was much smaller in predatory lines, and allele frequencies changed repeatably in predatory but not in aerobic lines. This suggests that more variants of smaller effects underlie variation in aerobic performance, whereas fewer variants of larger effects underlie variation in predatory behavior. Our results thus contradict the view that comparable selection pressures for different quantitative traits produce similar molecular patterns. Therefore, to gain knowledge about molecular-level response to selection for complex traits, we need to investigate not only multiple replicate populations but also multiple quantitative traits.
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Affiliation(s)
- Mateusz Konczal
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Paweł Koteja
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Patrycja Orlowska-Feuer
- Department of Neurophysiology and Chronobiology, Institute of Zoology, Jagiellonian University, Kraków, Poland
| | - Jacek Radwan
- Faculty of Biology, Institute of Environmental Biology, Adam Mickiewicz University, Poznań, Poland
| | - Edyta T Sadowska
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Wiesław Babik
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
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First asymmetric organocatalyzed domino Friedel–Crafts/lactonization reaction in the enantioselective synthesis of the GABAB receptor modulator (S)-BHFF. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.01.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Role of GABA(B) receptors in learning and memory and neurological disorders. Neurosci Biobehav Rev 2016; 63:1-28. [PMID: 26814961 DOI: 10.1016/j.neubiorev.2016.01.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/31/2015] [Accepted: 01/21/2016] [Indexed: 01/13/2023]
Abstract
Although it is evident from the literature that altered GABAB receptor function does affect behavior, these results often do not correspond well. These differences could be due to the task protocol, animal strain, ligand concentration, or timing of administration utilized. Because several clinical populations exhibit learning and memory deficits in addition to altered markers of GABA and the GABAB receptor, it is important to determine whether altered GABAB receptor function is capable of contributing to the deficits. The aim of this review is to examine the effect of altered GABAB receptor function on synaptic plasticity as demonstrated by in vitro data, as well as the effects on performance in learning and memory tasks. Finally, data regarding altered GABA and GABAB receptor markers within clinical populations will be reviewed. Together, the data agree that proper functioning of GABAB receptors is crucial for numerous learning and memory tasks and that targeting this system via pharmaceuticals may benefit several clinical populations.
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Pozdnyakova N, Dudarenko M, Borisova T. New effects of GABAB receptor allosteric modulator rac-BHFF on ambient GABA, uptake/release, Em and synaptic vesicle acidification in nerve terminals. Neuroscience 2015. [DOI: 10.1016/j.neuroscience.2015.07.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Borisova T, Nazarova A, Dekaliuk M, Krisanova N, Pozdnyakova N, Borysov A, Sivko R, Demchenko AP. Neuromodulatory properties of fluorescent carbon dots: Effect on exocytotic release, uptake and ambient level of glutamate and GABA in brain nerve terminals. Int J Biochem Cell Biol 2015; 59:203-15. [DOI: 10.1016/j.biocel.2014.11.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/12/2014] [Accepted: 11/28/2014] [Indexed: 11/24/2022]
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Filip M, Frankowska M, Sadakierska-Chudy A, Suder A, Szumiec Ł, Mierzejewski P, Bienkowski P, Przegaliński E, Cryan JF. GABAB receptors as a therapeutic strategy in substance use disorders: Focus on positive allosteric modulators. Neuropharmacology 2015; 88:36-47. [DOI: 10.1016/j.neuropharm.2014.06.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/10/2014] [Accepted: 06/15/2014] [Indexed: 12/16/2022]
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Kalinichev M, Le Poul E, Boléa C, Girard F, Campo B, Fonsi M, Royer-Urios I, Browne SE, Uslaner JM, Davis MJ, Raber J, Duvoisin R, Bate ST, Reynolds IJ, Poli S, Celanire S. Characterization of the novel positive allosteric modulator of the metabotropic glutamate receptor 4 ADX88178 in rodent models of neuropsychiatric disorders. J Pharmacol Exp Ther 2014; 350:495-505. [PMID: 24947466 DOI: 10.1124/jpet.114.214437] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is growing evidence that activation of metabotropic glutamate receptor 4 (mGlu4) leads to anxiolytic- and antipsychotic-like efficacy in rodent models, yet its relevance to depression-like reactivity remains unclear. Here, we present the pharmacological evaluation of ADX88178 [5-methyl-N-(4-methylpyrimidin-2-yl)-4-(1H-pyrazol-4-yl)thiazol-2-amine], a novel potent, selective, and brain-penetrant positive allosteric modulator of the mGlu4 receptor in rodent models of anxiety, obsessive compulsive disorder (OCD), fear, depression, and psychosis. ADX88178 dose-dependently reduced the number of buried marbles in the marble burying test and increased open-arm exploration in the elevated plus maze (EPM) test, indicative of anxiolytic-like efficacy. Target specificity of the effect in the EPM test was confirmed using male and female mGlu4 receptor knockout mice. In mice, ADX88178 reduced the likelihood of conditioned freezing in the acquisition phase of the fear conditioning test, yet had no carryover effect in the expression phase. Also, ADX88178 dose-dependently reduced duration of immobility in the forced swim test, indicative of antidepressant-like efficacy. ADX88178 reduced DOI (2,5-dimethoxy-4-iodoamphetamine)-mediated head twitches (albeit with no dose-dependency), and MK-801 [(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine]-induced locomotor hyperactivity in mice, but was inactive in the conditioned avoidance response test in rats. The compound showed good specificity as it had no effect on locomotor activity in mice and rats at efficacious doses. Thus, allosteric activation of mGlu4 receptors can be a promising new therapeutic approach for treatment of anxiety, OCD, fear-related disorders, and psychosis.
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Affiliation(s)
- Mikhail Kalinichev
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Emmanuel Le Poul
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Christelle Boléa
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Françoise Girard
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Brice Campo
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Massimiliano Fonsi
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Isabelle Royer-Urios
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Susan E Browne
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Jason M Uslaner
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Matthew J Davis
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Jacob Raber
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Robert Duvoisin
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Simon T Bate
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Ian J Reynolds
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Sonia Poli
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Sylvain Celanire
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
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Ostrovskaya O, Xie K, Masuho I, Fajardo-Serrano A, Lujan R, Wickman K, Martemyanov KA. RGS7/Gβ5/R7BP complex regulates synaptic plasticity and memory by modulating hippocampal GABABR-GIRK signaling. eLife 2014; 3:e02053. [PMID: 24755289 PMCID: PMC3988575 DOI: 10.7554/elife.02053] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the hippocampus, the inhibitory neurotransmitter GABA shapes the activity of the output pyramidal neurons and plays important role in cognition. Most of its inhibitory effects are mediated by signaling from GABAB receptor to the G protein-gated Inwardly-rectifying K+ (GIRK) channels. Here, we show that RGS7, in cooperation with its binding partner R7BP, regulates GABABR-GIRK signaling in hippocampal pyramidal neurons. Deletion of RGS7 in mice dramatically sensitizes GIRK responses to GABAB receptor stimulation and markedly slows channel deactivation kinetics. Enhanced activity of this signaling pathway leads to decreased neuronal excitability and selective disruption of inhibitory forms of synaptic plasticity. As a result, mice lacking RGS7 exhibit deficits in learning and memory. We further report that RGS7 is selectively modulated by its membrane anchoring subunit R7BP, which sets the dynamic range of GIRK responses. Together, these results demonstrate a novel role of RGS7 in hippocampal synaptic plasticity and memory formation. DOI:http://dx.doi.org/10.7554/eLife.02053.001 Neurons communicate with one another at junctions called synapses. The arrival of an electrical signal known as an action potential at the first cell causes molecules known as neurotransmitters to be released into the synapse. These molecules diffuse across the gap between the neurons and bind to receptors on the receiving cell. Some neurotransmitters, such as glutamate, activate cells when they bind to receptors, thus making it easier for the second neuron to ‘fire’ (i.e., to generate an action potential). By contrast, other neurotransmitters, such as GABA, usually make it harder for the second neuron to fire. Many of the effects of GABA involve a type of receptor called GABAB. When GABA binds to one of these receptors, a molecule called a G-protein is recruited to the receptor. This activates the G-protein, triggering a cascade of events inside the cell that lead ultimately to the opening of potassium ion channels, which as known as GIRKs, in the cell membrane. Positively charged potassium ions then leave the cell through these channels, and this makes it more difficult for the cell to fire. Now, Ostrovskaya et al. have revealed that a complex of three proteins regulates the interaction between GABAB receptors and GIRK channels. In neurons that lack either of these proteins, the receptors have less influence on GIRKs than in normal cells. Moreover, mice that lack one of the proteins (called RGS7) perform less well in various learning and memory tests: for example, they take longer than normal animals to learn the location of an escape platform in a water maze, or to retain a memory of a fearful event. By identifying the proteins that regulate the interaction between GABAB receptors and GIRKs, Ostrovskaya et al. have helped to unravel a key signaling cascade relevant to cognition. Given that GIRK channels have recently been implicated in Down’s syndrome, these insights may also increase understanding of cognitive impairments in neuropsychiatric disorders. DOI:http://dx.doi.org/10.7554/eLife.02053.002
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Affiliation(s)
- Olga Ostrovskaya
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
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McCarson KE, Enna SJ. GABA pharmacology: the search for analgesics. Neurochem Res 2014; 39:1948-63. [PMID: 24532294 DOI: 10.1007/s11064-014-1254-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/28/2014] [Accepted: 01/31/2014] [Indexed: 12/28/2022]
Abstract
Decades of research have been devoted to defining the role of GABAergic transmission in nociceptive processing. Much of this work was performed using rigid, orthosteric GABA analogs created by Povl Krogsgaard-Larsen and his associates. A relationship between GABA and pain is suggested by the anatomical distribution of GABA receptors and the ability of some GABA agonists to alter nociceptive responsiveness. Outlined in this report are data supporting this proposition, with particular emphasis on the anatomical localization and function of GABA-containing neurons and the molecular and pharmacological properties of GABAA and GABAB receptor subtypes. Reference is made to changes in overall GABAergic tone, GABA receptor expression and activity as a function of the duration and intensity of a painful stimulus or exposure to GABAergic agents. Evidence is presented that the plasticity of this receptor system may be responsible for the variability in the antinociceptive effectiveness of compounds that influence GABA transmission. These findings demonstrate that at least some types of persistent pain are associated with a regionally selective decline in GABAergic tone, highlighting the need for agents that enhance GABA activity in the affected regions without compromising GABA function over the long-term. As subtype selective positive allosteric modulators may accomplish these goals, such compounds might represent a new class of analgesic drugs.
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Affiliation(s)
- Kenneth E McCarson
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Mail Stop 1018, Kansas City, KS, 66160, USA
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Vetica F, Pelosi A, Gambacorta A, Loreto MA, Miceli M, Gasperi T. Catalytic Friedel-Crafts/Lactonization Domino Reaction: Facile Access to 3-Hydroxybenzofuran-2-one Scaffold. European J Org Chem 2014. [DOI: 10.1002/ejoc.201301686] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Koek W, Cheng K, Rice KC. Discriminative stimulus effects of the GABAB receptor-positive modulator rac-BHFF: comparison with GABAB receptor agonists and drugs of abuse. J Pharmacol Exp Ther 2012; 344:553-60. [PMID: 23275067 DOI: 10.1124/jpet.112.202226] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
GABA(B) receptor-positive modulators are thought to have advantages as potential medications for anxiety, depression, and drug addiction. They may have fewer side effects than GABA(B) receptor agonists, because selective enhancement of activated receptors could have effects different from nonselective activation of all receptors. To examine this, pigeons were trained to discriminate the GABA(B) receptor-positive modulator (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) from its vehicle. The discriminative stimulus effects of rac-BHFF were not mimicked by the GABA(B) receptor agonists baclofen and γ-hydroxybutyrate (GHB), not by diazepam, and not by alcohol, cocaine, and nicotine, whose self-administration has been reported to be attenuated by GABA(B) receptor-positive modulators. The discriminative stimulus effects of rac-BHFF were not antagonized by the GABA(B) receptor antagonist 3-aminopropyl (diethoxymethyl)phosphinic acid (CGP35348) but were attenuated by the less efficacious GABA(B) receptor-positive modulator 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl)phenol (CGP7930), suggesting the possibility that rac-BHFF produces its discriminative stimulus effects by directly activating GABA(B2) subunits of GABA(B) receptors. At a dose 10-fold lower than the training dose, rac-BHFF enhanced the discriminative stimulus effects of baclofen, but not of GHB. This study provides evidence that the effects of GABA(B) receptor-positive modulators are not identical to those of GABA(B) receptor agonists. In addition, the results suggest that positive modulation of GABA(B) receptors does not produce discriminative stimulus effects similar to those of benzodiazepines, alcohol, cocaine, and nicotine. Finally, the finding that rac-BHFF enhanced effects of baclofen but not of GHB is consistent with converging evidence that the populations of GABA(B) receptors mediating the effects of baclofen and GHB are not identical.
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Affiliation(s)
- Wouter Koek
- Department of Psychiatry and Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, Mail Code 7792, San Antonio, TX, USA.
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Holstein SE, Li N, Eshleman AJ, Phillips TJ. GABAB receptor activation attenuates the stimulant but not mesolimbic dopamine response to ethanol in FAST mice. Behav Brain Res 2012; 237:49-58. [PMID: 22982185 DOI: 10.1016/j.bbr.2012.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 08/14/2012] [Accepted: 09/05/2012] [Indexed: 12/20/2022]
Abstract
Neural processes influenced by γ-aminobutyric acid B (GABA(B)) receptors appear to contribute to acute ethanol sensitivity, including the difference between lines of mice bred for extreme sensitivity (FAST) or insensitivity (SLOW) to the locomotor stimulant effect of ethanol. One goal of the current study was to determine whether selection of the FAST and SLOW lines resulted in changes in GABA(B) receptor function, since the lines differ in sensitivity to the GABA(B) receptor agonist baclofen and baclofen attenuates the stimulant response to ethanol in FAST mice. A second goal was to determine whether the baclofen-induced reduction in ethanol stimulation in FAST mice is associated with an attenuation of the mesolimbic dopamine response to ethanol. In Experiment 1, the FAST and SLOW lines were found to not differ in GABA(B) receptor function (measured by baclofen-stimulated [(35)S]GTPγS binding) in whole brain or in several regional preparations, except in the striatum in one of the two replicate sets of selected lines. In Experiment 2, baclofen-induced attenuation of the locomotor stimulant response to ethanol in FAST mice was not accompanied by a reduction in dopamine levels in the nucleus accumbens, as measured by microdialysis. These data suggest that, overall, GABA(B) receptor function does not play an integral role in the genetic difference in ethanol sensitivity between the FAST and SLOW lines. Further, although GABA(B) receptors do modulate the locomotor stimulant response to ethanol in FAST mice, this effect does not appear to be due to a reduction in tonic dopamine signaling in the nucleus accumbens.
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Affiliation(s)
- Sarah E Holstein
- Dept of Behavioral Neuroscience and Portland Alcohol Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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Koek W, France CP, Cheng K, Rice KC. Effects of the GABAB receptor-positive modulators CGP7930 and rac-BHFF in baclofen- and γ-hydroxybutyrate-discriminating pigeons. J Pharmacol Exp Ther 2012; 341:369-76. [PMID: 22319197 DOI: 10.1124/jpet.111.190975] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In vivo effects of GABA(B) receptor-positive modulators suggest them to have therapeutic potential to treat central nervous system disorders such as anxiety and drug abuse. Although these effects are thought to be mediated by positive modulation of GABA(B) receptors, such modulation has been examined primarily in vitro. This study further examined the in vivo properties of the GABA(B) receptor-positive modulators 2,6-di-tert-butyl-4-(3-hydroxy-2,2-dimethylpropyl) phenol (CGP7930) and (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF). In pigeons discriminating baclofen from saline, γ-hydroxybutyrate (GHB) produced 100% baclofen-appropriate responding, and the GABA(B) antagonist 3-aminopropyl(dimethoxymethyl) phosphinic acid (CGP35348) blocked the effects of both drugs. CGP7930 and rac-BHFF produced at most 41 and 74% baclofen-appropriate responding, respectively, and enhanced the discriminative stimulus effects of baclofen, but not of GHB. In pigeons discriminating GHB from saline, CGP7930 and rac-BHFF produced at most 1 and 49% GHB-appropriate responding, respectively, and enhanced the effects of baclofen, but not of GHB. Enhancement of the discriminative stimulus effects of baclofen by rac-BHFF and CGP7930 is further evidence of their effectiveness as GABA(B) receptor-positive modulators in vivo. Furthermore, lack of complete substitution of the positive modulators rac-BHFF and CGP7930 for baclofen and GHB suggests that their discriminative stimulus effects differ from those of GABA(B) receptor agonists. Finally, together with converging evidence that the GABA(B) receptor populations mediating the effects of baclofen and GHB are not identical, the present findings suggest that these populations differ in their susceptibility to positive modulatory effects. Such differences could allow for more selective therapeutic targeting of the GABA(B) system.
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Affiliation(s)
- Wouter Koek
- Departments of Psychiatry and Pharmacology, University of Texas Health Science Center, 7703 Floyd Curl Drive, Mail Code 7792, San Antonio, TX 78229-3900, USA.
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