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Abbondanza A, Urushadze A, Alves-Barboza AR, Janickova H. Expression and function of nicotinic acetylcholine receptors in specific neuronal populations: Focus on striatal and prefrontal circuits. Pharmacol Res 2024; 204:107190. [PMID: 38704107 DOI: 10.1016/j.phrs.2024.107190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/19/2024] [Accepted: 04/20/2024] [Indexed: 05/06/2024]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are widely expressed in the central nervous system and play an important role in the control of neural functions including neuronal activity, transmitter release and synaptic plasticity. Although the common subtypes of nAChRs are abundantly expressed throughout the brain, their expression in different brain regions and by individual neuronal types is not homogeneous or incidental. In recent years, several studies have emerged showing that particular subtypes of nAChRs are expressed by specific neuronal populations in which they have major influence on the activity of local circuits and behavior. It has been demonstrated that even nAChRs expressed by relatively rare neuronal types can induce significant changes in behavior and contribute to pathological processes. Depending on the identity and connectivity of the particular nAChRs-expressing neuronal populations, the activation of nAChRs can have distinct or even opposing effects on local neuronal signaling. In this review, we will summarize the available literature describing the expression of individual nicotinic subunits by different neuronal types in two crucial brain regions, the striatum and the prefrontal cortex. The review will also briefly discuss nicotinic expression in non-neuronal, glial cells, as they cannot be ignored as potential targets of nAChRs-modulating drugs. The final section will discuss options that could allow us to target nAChRs in a neuronal-type-specific manner, not only in the experimental field, but also eventually in clinical practice.
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Affiliation(s)
- Alice Abbondanza
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic
| | - Anna Urushadze
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic
| | - Amanda Rosanna Alves-Barboza
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic
| | - Helena Janickova
- Laboratory of Neurochemistry, Institute of Physiology of the Czech Academy of Sciences, Prague 14200, Czech Republic.
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2
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Li ZL, Gou CY, Wang WH, Li Y, Cui Y, Duan JJ, Chen Y. A novel effect of PDLIM5 in α7 nicotinic acetylcholine receptor upregulation and surface expression. Cell Mol Life Sci 2022; 79:64. [PMID: 35013841 PMCID: PMC11072317 DOI: 10.1007/s00018-021-04115-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/17/2021] [Accepted: 12/23/2021] [Indexed: 11/29/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are widespread throughout the central nervous system. Signaling through nAChRs contributes to numerous higher-order functions, including memory and cognition, as well as abnormalities such as nicotine addiction and neurodegenerative disorders. Although recent studies indicate that the PDZ-containing proteins comprising PSD-95 family co-localize with nicotinic acetylcholine receptors and mediate downstream signaling in the neurons, the mechanisms by which α7nAChRs are regulated remain unclear. Here, we show that the PDZ-LIM domain family protein PDLIM5 binds to α7nAChRs and plays a role in nicotine-induced α7nAChRs upregulation and surface expression. We find that chronic exposure to 1 μM nicotine upregulated α7, β2-contained nAChRs and PDLIM5 in cultured hippocampal neurons, and the upregulation of α7nAChRs and PDLIM5 is increased more on the cell membrane than the cytoplasm. Interestingly, in primary hippocampal neurons, α7nAChRs and β2nAChRs display distinct patterns of expression, with α7nAChRs colocalized more with PDLIM5. Furthermore, PDLIM5 interacts with α7nAChRs, but not β2nAChRs in native brain neurons. Knocking down of PDLIM5 in SH-SY5Y abolishes nicotine-induced upregulation of α7nAChRs. In primary hippocampal neurons, using shRNA against PDLIM5 decreased both surface clustering of α7nAChRs and α7nAChRs-mediated currents. Proteomics analysis and isothermal titration calorimetry (ITC) results show that PDLIM5 interacts with α7nAChRs through the PDZ domain, and the interaction between PDLIM5 and α7nAChRs can be promoted by nicotine. Collectively, our data suggest a novel cellular role of PDLIM5 in the regulation of α7nAChRs, which may be relevant to plastic changes in the nervous system.
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Affiliation(s)
- Zi-Lin Li
- Neurobiology Research Center, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, 518107, Guangdong, People's Republic of China
| | - Chen-Yu Gou
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzho, 510080, Guangdong, People's Republic of China
| | - Wen-Hui Wang
- Neurobiology Research Center, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, 518107, Guangdong, People's Republic of China
| | - Yuan Li
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzho, 510080, Guangdong, People's Republic of China
| | - Yu Cui
- Neurobiology Research Center, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, 518107, Guangdong, People's Republic of China
| | - Jing-Jing Duan
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzho, 510080, Guangdong, People's Republic of China.
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, Guangdong, People's Republic of China.
| | - Yuan Chen
- Neurobiology Research Center, School of Medicine, Shenzhen Campus of Sun Yat-Sen University, No. 66, Gongchang Road, Guangming District, Shenzhen, 518107, Guangdong, People's Republic of China.
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Fear learning induces α7-nicotinic acetylcholine receptor-mediated astrocytic responsiveness that is required for memory persistence. Nat Neurosci 2021; 24:1686-1698. [PMID: 34782794 DOI: 10.1038/s41593-021-00949-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/27/2021] [Indexed: 01/28/2023]
Abstract
Memory persistence is a fundamental cognitive process for guiding behaviors and is considered to rely mostly on neuronal and synaptic plasticity. Whether and how astrocytes contribute to memory persistence is largely unknown. Here, by using two-photon Ca2+ imaging in head-fixed mice and fiber photometry in freely moving mice, we show that aversive sensory stimulation activates α7-nicotinic acetylcholine receptors (nAChRs) in a subpopulation of astrocytes in the auditory cortex. We demonstrate that fear learning causes the de novo induction of sound-evoked Ca2+ transients in these astrocytes. The astrocytic responsiveness persisted over days along with fear memory and disappeared in animals that underwent extinction of learned freezing behavior. Conditional genetic deletion of α7-nAChRs in astrocytes significantly impaired fear memory persistence. We conclude that learning-acquired, α7-nAChR-dependent astrocytic responsiveness is an integral part of the cellular substrate underlying memory persistence.
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Aryal SP, Fu X, Sandin JN, Neupane KR, Lakes JE, Grady ME, Richards CI. Nicotine induces morphological and functional changes in astrocytes via nicotinic receptor activity. Glia 2021; 69:2037-2053. [PMID: 33851731 DOI: 10.1002/glia.24011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/26/2021] [Accepted: 04/08/2021] [Indexed: 01/16/2023]
Abstract
Nicotine is a highly addictive compound present in tobacco, which causes the release of dopamine in different regions of the brain. Recent studies have shown that astrocytes express nicotinic acetylcholine receptors (nAChRs) and mediate calcium signaling. In this study, we examine the morphological and functional adaptations of astrocytes due to nicotine exposure. Utilizing a combination of fluorescence and atomic force microscopy, we show that nicotine-treated astrocytes exhibit time-dependent remodeling in the number and length of both proximal and fine processes. Blocking nAChR activity with an antagonist completely abolishes nicotine's influence on astrocyte morphology indicating that nicotine's action is mediated by these receptors. Functional studies show that 24-hr nicotine treatment induces higher levels of calcium activity in both the cell soma and the processes with a more substantial change observed in the processes. Nicotine does not induce reactive astrocytosis even at high concentrations (10 μM) as determined by cytokine release and glial fibrillary acidic protein expression. We designed tissue clearing experiments to test whether morphological changes occur in vivo using astrocyte specific Aldh1l1-tdTomato knock in mice. We find that nicotine induces a change in the volume of astrocytes in the prefrontal cortex, CA1 of the hippocampus, and the substantia nigra. These results indicate that nicotine directly alters the functional and morphological properties of astrocytes potentially contributing to the underlying mechanism of nicotine abuse.
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Affiliation(s)
- Surya P Aryal
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Xu Fu
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Joree N Sandin
- Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky, USA
| | - Khaga R Neupane
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Jourdan E Lakes
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Martha E Grady
- Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky, USA
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Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
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Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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Booth S, Ramadan A, Zhang D, Lu L, Kirouac G, Jackson MF, Anderson C, Ko JH. The Vasomotor Response to Dopamine Is Altered in the Rat Model of l-dopa-Induced Dyskinesia. Mov Disord 2021; 36:938-947. [PMID: 33135810 PMCID: PMC8246949 DOI: 10.1002/mds.28357] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/08/2020] [Accepted: 10/01/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Levodopa (l-dopa) is the frontline treatment for motor symptoms of Parkinson's disease. However, prolonged use of l-dopa results in a motor complication known as levodopa-induced dyskinesia (LID) in ~50% of patients over 5 years. OBJECTIVES We investigated neurovascular abnormalities in a rat model of LID by examining changes in angiogenesis and dopamine-dependent vessel diameter changes. METHODS Differences in striatal and nigral angiogenesis in a parkinsonian rat model (6-OHDA lesion) treated with 2 doses of l-dopa (saline, 2, and 10 mg/kg/day subcutaneous l-dopa treatment for 22 days) by 5-bromo-2'-deoxyuridine (BrdU)-RECA1 co-immunofluorescence. Difference in the vasomotor response to dopamine was examined with 2-photon laser scanning microscopy and Dodt gradient imaging. RESULTS We found that the 10 mg/kg l-dopa dosing regimen induced LID in all animals (n = 5) and induced significant angiogenesis in the striatum and substantia nigra. In contrast, the 2 mg/kg treatment induced LID in 6 out of 12 rats and led to linearly increasing LID severity over the 22-day treatment period, making this a promising model for studying LID progression longitudinally. However, no significantly different level of angiogenesis was observed between LID versus non-LID animals. Dopamine-induced vasodilatory responses were exaggerated only in rats that show LID-like signs compared to the rest of groups. Additionally, in juvenile rats, we showed that DA-induced vasodilation is preceded by increased Ca2+ release in the adjacent astrocytes. CONCLUSION This finding supports that astrocytic dopamine signaling controls striatal blood flow bidirectionally, and the balance is altered in LID. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Samuel Booth
- Department of Human Anatomy and Cell ScienceUniversity of ManitobaWinnipegManitobaCanada
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
| | - Abdullah Ramadan
- Department of Human Anatomy and Cell ScienceUniversity of ManitobaWinnipegManitobaCanada
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
| | - Dali Zhang
- Department of Human Anatomy and Cell ScienceUniversity of ManitobaWinnipegManitobaCanada
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
| | - Lingling Lu
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
- Department of Pharmacology and TherapeuticsUniversity of ManitobaWinnipegManitobaCanada
| | - Gilbert Kirouac
- Department of Oral BiologyUniversity of ManitobaWinnipegManitobaCanada
| | - Michael F. Jackson
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
- Department of Pharmacology and TherapeuticsUniversity of ManitobaWinnipegManitobaCanada
| | - Chris Anderson
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
- Department of Pharmacology and TherapeuticsUniversity of ManitobaWinnipegManitobaCanada
| | - Ji Hyun Ko
- Department of Human Anatomy and Cell ScienceUniversity of ManitobaWinnipegManitobaCanada
- Kleyson Institute for Advanced MedicineHealth Science CentreWinnipegManitobaCanada
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Secci ME, Mascia P, Sagheddu C, Beggiato S, Melis M, Borelli AC, Tomasini MC, Panlilio LV, Schindler CW, Tanda G, Ferré S, Bradberry CW, Ferraro L, Pistis M, Goldberg SR, Schwarcz R, Justinova Z. Astrocytic Mechanisms Involving Kynurenic Acid Control Δ 9-Tetrahydrocannabinol-Induced Increases in Glutamate Release in Brain Reward-Processing Areas. Mol Neurobiol 2018; 56:3563-3575. [PMID: 30151725 DOI: 10.1007/s12035-018-1319-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/14/2018] [Indexed: 12/27/2022]
Abstract
The reinforcing effects of Δ9-tetrahydrocannabinol (THC) in rats and monkeys, and the reinforcement-related dopamine-releasing effects of THC in rats, can be attenuated by increasing endogenous levels of kynurenic acid (KYNA) through systemic administration of the kynurenine 3-monooxygenase inhibitor, Ro 61-8048. KYNA is a negative allosteric modulator of α7 nicotinic acetylcholine receptors (α7nAChRs) and is synthesized and released by astroglia, which express functional α7nAChRs and cannabinoid CB1 receptors (CB1Rs). Here, we tested whether these presumed KYNA autoreceptors (α7nAChRs) and CB1Rs regulate glutamate release. We used in vivo microdialysis and electrophysiology in rats, RNAscope in situ hybridization in brain slices, and primary culture of rat cortical astrocytes. Acute systemic administration of THC increased extracellular levels of glutamate in the nucleus accumbens shell (NAcS), ventral tegmental area (VTA), and medial prefrontal cortex (mPFC). THC also reduced extracellular levels of KYNA in the NAcS. These THC effects were prevented by administration of Ro 61-8048 or the CB1R antagonist, rimonabant. THC increased the firing activity of glutamatergic pyramidal neurons projecting from the mPFC to the NAcS or to the VTA in vivo. These effects were averted by pretreatment with Ro 61-8048. In vitro, THC elicited glutamate release from cortical astrocytes (on which we demonstrated co-localization of the CB1Rs and α7nAChR mRNAs), and this effect was prevented by KYNA and rimonabant. These results suggest a key role of astrocytes in interactions between the endocannabinoid system, kynurenine pathway, and glutamatergic neurotransmission, with ramifications for the pathophysiology and treatment of psychiatric and neurodegenerative diseases.
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Affiliation(s)
- Maria E Secci
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Paola Mascia
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Claudia Sagheddu
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Sarah Beggiato
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Andrea C Borelli
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Maria C Tomasini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Leigh V Panlilio
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Charles W Schindler
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Gianluigi Tanda
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Sergi Ferré
- Molecular Targets and Medications Discovery Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Charles W Bradberry
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Luca Ferraro
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Marco Pistis
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
- National Research Council of Italy (CNR), Section of Cagliari, Neuroscience Institute, Monserrato, Italy
| | - Steven R Goldberg
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Zuzana Justinova
- Behavioral Neuroscience Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Blvd., Baltimore, MD, 21224, USA.
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8
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Liu Q, Liu C, Jiang L, Li M, Long T, He W, Qin G, Chen L, Zhou J. α7 Nicotinic acetylcholine receptor-mediated anti-inflammatory effect in a chronic migraine rat model via the attenuation of glial cell activation. J Pain Res 2018; 11:1129-1140. [PMID: 29942148 PMCID: PMC6007207 DOI: 10.2147/jpr.s159146] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background Evidence suggests that the activation of α7 nicotinic acetylcholine receptor (α7nAChR) can greatly decrease the neuroinflammation response. Neuroinflammation plays a pivotal role in the pathogenesis of chronic migraine (CM). Clinical observations also show that nicotine gum induces analgesic effects in migraine patients. However, whether α7nAChR is involved in CM is unclear. Objective To investigate the role of α7nAChR in CM and provide a new therapeutic target for CM. Materials and methods Thirty-six male Sprague–Dawley rats were distributed randomly into control, CM, PNU-282987, and α-bungarotoxin groups (n=9 rats in each group). The CM model was established by the recurrent daily administration of inflammatory soup on the dura over the course of 1 week. The hind paw threshold and facial allodynia were assessed by the von Frey test. The expression levels of α7nAChR, tumor necrosis factor-alpha, and interleukin-1 beta were analyzed by Western blot and real-time fluorescence quantitative polymerase chain reaction. The location of α7nAChR in the hippocampus was quantified by immunofluorescence, as well as the microglial and astrocyte alterations. Changes in the calcitonin gene-related peptide and the phosphorylated JNK protein among different groups were measured by Western blot. Results We found that the expression of α7nAChR was reduced after repeated inflammatory soup administration. The increased expression of tumor necrosis factor-alpha, interleukin-1 beta, and calcitonin gene-related peptide in CM group were significantly decreased by PNU-282987 and aggravated by α-bungarotoxin. Moreover, PNU-282987 decreased the numbers of astrocytes and microglia compared with the numbers in the CM group in both hippocampal CA1 and CA3 regions. In contrast, α-bungarotoxin activated the astrocytes and microglia, but the differences with respect to the CM group were not significant. Activated c-Jun N-terminal kinase signaling was observed in CM rats and was also blocked by PNU-282987. Conclusion The activation of α7nAChR increased the mechanical threshold and alleviated pain in the CM rat model. α7nAChR activation also decreased the upregulation of astrocytes and microglia through the p-c-Jun N-terminal kinase–mitogen-activated protein kinase signaling pathway.
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Affiliation(s)
- Qing Liu
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Chaoyang Liu
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Li Jiang
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Maolin Li
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Ting Long
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Wei He
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Guangcheng Qin
- Laboratory Research Center, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Lixue Chen
- Laboratory Research Center, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Jiying Zhou
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
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9
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Gielen M, Corringer P. The dual-gate model for pentameric ligand-gated ion channels activation and desensitization. J Physiol 2018; 596:1873-1902. [PMID: 29484660 PMCID: PMC5978336 DOI: 10.1113/jp275100] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 01/17/2018] [Accepted: 01/17/2018] [Indexed: 12/15/2022] Open
Abstract
Pentameric ligand-gated ion channels (pLGICs) mediate fast neurotransmission in the nervous system. Their dysfunction is associated with psychiatric, neurological and neurodegenerative disorders such as schizophrenia, epilepsy and Alzheimer's disease. Understanding their biophysical and pharmacological properties, at both the functional and the structural level, thus holds many therapeutic promises. In addition to their agonist-elicited activation, most pLGICs display another key allosteric property, namely desensitization, in which they enter a shut state refractory to activation upon sustained agonist binding. While the activation mechanisms of several pLGICs have been revealed at near-atomic resolution, the structural foundation of desensitization has long remained elusive. Recent structural and functional data now suggest that the activation and desensitization gates are distinct, and are located at both sides of the ion channel. Such a 'dual gate mechanism' accounts for the marked allosteric effects of channel blockers, a feature illustrated herein by theoretical kinetics simulations. Comparison with other classes of ligand- and voltage-gated ion channels shows that this dual gate mechanism emerges as a common theme for the desensitization and inactivation properties of structurally unrelated ion channels.
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Affiliation(s)
- Marc Gielen
- Channel Receptors UnitInstitut PasteurCNRS UMR 3571ParisFrance
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10
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Mei YY, Wu DC, Zhou N. Astrocytic Regulation of Glutamate Transmission in Schizophrenia. Front Psychiatry 2018; 9:544. [PMID: 30459650 PMCID: PMC6232167 DOI: 10.3389/fpsyt.2018.00544] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/12/2018] [Indexed: 01/19/2023] Open
Abstract
According to the glutamate hypothesis of schizophrenia, the abnormality of glutamate transmission induced by hypofunction of NMDA receptors (NMDARs) is causally associated with the positive and negative symptoms of schizophrenia. However, the underlying mechanisms responsible for the changes in glutamate transmission in schizophrenia are not fully understood. Astrocytes, the major regulatory glia in the brain, modulate not only glutamate metabolism but also glutamate transmission. Here we review the recent progress in understanding the role of astrocytes in schizophrenia. We focus on the astrocytic mechanisms of (i) glutamate synthesis via the glutamate-glutamine cycle, (ii) glutamate clearance by excitatory amino acid transporters (EAATs), (iii) D-serine release to activate NMDARs, and (iv) glutamatergic target engagement biomarkers. Abnormality in these processes is highly correlated with schizophrenia phenotypes. These findings will shed light upon further investigation of pathogenesis as well as improvement of biomarkers and therapies for schizophrenia.
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Affiliation(s)
- Yu-Ying Mei
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Dong Chuan Wu
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Ning Zhou
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
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11
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Bortz DM, Wu HQ, Schwarcz R, Bruno JP. Oral administration of a specific kynurenic acid synthesis (KAT II) inhibitor attenuates evoked glutamate release in rat prefrontal cortex. Neuropharmacology 2017; 121:69-78. [PMID: 28419874 PMCID: PMC5803791 DOI: 10.1016/j.neuropharm.2017.04.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/22/2017] [Accepted: 04/14/2017] [Indexed: 11/20/2022]
Abstract
Cognitive deficits represent core symptoms in schizophrenia (SZ) and predict patient outcome; however, they remain poorly treated by current antipsychotic drugs. Elevated levels of the endogenous alpha7 nicotinic receptor negative allosteric modulator and NMDA receptor antagonist, kynurenic acid (KYNA), are commonly seen in post-mortem tissue and cerebrospinal fluid of patients with SZ. When acutely or chronically elevated in rodents, KYNA produces cognitive deficits similar to those seen in the disease, making down-regulation of KYNA, via inhibition of kynurenine aminotransferase II (KAT II), a potential treatment strategy. We determined, in adult Wistar rats, if the orally available KAT II inhibitor BFF816 a) prevents KYNA elevations in prefrontal cortex (PFC) after a systemic kynurenine injection and b) reverses the kynurenine-induced attenuation of evoked prefrontal glutamate release caused by stimulation of the nucleus accumbens shell (NAcSh). Systemic injection of kynurenine (25 or 100 mg/kg, i.p.) increased KYNA levels in PFC (532% and 1104% of baseline, respectively). NMDA infusions (0.15 μg/0.5 μL) into NAcSh raised prefrontal glutamate levels more than 30-fold above baseline. The two doses of kynurenine reduced evoked glutamate release in PFC (by 43% and 94%, respectively, compared to NMDA alone). Co-administration of BFF816 (30 or 100 mg/kg, p.o.) with kynurenine (25 mg/kg, i.p.) attenuated the neosynthesis of KYNA and dose-dependently restored NMDA-stimulated glutamate release in the PFC (16% and 69%, respectively). The ability to prevent KYNA neosynthesis and to normalize evoked glutamate release in PFC justifies further development of KAT II inhibitors for the treatment of cognitive deficits in SZ.
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Affiliation(s)
- D M Bortz
- Dept. of Psychology, The Ohio State University, Columbus, OH, United States
| | - H-Q Wu
- Maryland Psychiatric Research Center, Dept. of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States
| | - R Schwarcz
- Maryland Psychiatric Research Center, Dept. of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States
| | - J P Bruno
- Dept. of Psychology, The Ohio State University, Columbus, OH, United States; Dept. of Neuroscience, The Ohio State University, Columbus, OH, United States.
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12
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Papouin T, Dunphy JM, Tolman M, Dineley KT, Haydon PG. Septal Cholinergic Neuromodulation Tunes the Astrocyte-Dependent Gating of Hippocampal NMDA Receptors to Wakefulness. Neuron 2017; 94:840-854.e7. [PMID: 28479102 PMCID: PMC5484087 DOI: 10.1016/j.neuron.2017.04.021] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/24/2017] [Accepted: 04/12/2017] [Indexed: 12/21/2022]
Abstract
The activation of the N-methyl D-aspartate receptor (NMDAR) is controlled by a glutamate-binding site and a distinct, independently regulated, co-agonist-binding site. In most brain regions, the NMDAR co-agonist is the astrocyte-derived gliotransmitter D-serine. We found that D-serine levels oscillate in mouse hippocampus as a function of wakefulness, in vitro and in vivo. This causes a full saturation of the NMDAR co-agonist site in the dark (active) phase that dissipates to sub-saturating levels during the light (sleep) phase, and influences learning performance throughout the day. We demonstrate that hippocampal astrocytes sense the wakefulness-dependent activity of septal cholinergic fibers through the α7-nicotinic acetylcholine receptor (α7nAChR), whose activation drives D-serine release. We conclude that astrocytes tune the gating of synaptic NMDARs to the vigilance state and demonstrate that this is directly relevant to schizophrenia, a disorder characterized by NMDAR and cholinergic hypofunctions. Indeed, bypassing cholinergic activity with a clinically tested α7nAChR agonist successfully enhances NMDAR activation. VIDEO ABSTRACT.
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Affiliation(s)
- Thomas Papouin
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Jaclyn M Dunphy
- Neuroscience Program, Tufts Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA
| | - Michaela Tolman
- Neuroscience Program, Tufts Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA
| | - Kelly T Dineley
- Department of Neurology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, USA.
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13
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Peterson DJ, Gill WD, Dose JM, Hoover DB, Pauly JR, Cummins ED, Burgess KC, Brown RW. The effects of nicotine in the neonatal quinpirole rodent model of psychosis: Neural plasticity mechanisms and nicotinic receptor changes. Behav Brain Res 2017; 325:17-24. [PMID: 28235586 DOI: 10.1016/j.bbr.2017.02.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/16/2017] [Accepted: 02/18/2017] [Indexed: 01/06/2023]
Abstract
Neonatal quinpirole (NQ) treatment to rats increases dopamine D2 receptor sensitivity persistent throughout the animal's lifetime. In Experiment 1, we analyzed the role of α7 and α4β2 nicotinic receptors (nAChRs) in nicotine behavioral sensitization and on the brain-derived neurotrophic factor (BDNF) response to nicotine in NQ- and neonatally saline (NS)-treated rats. In Experiment 2, we analyzed changes in α7 and α4β2 nAChR density in the nucleus accumbens (NAcc) and dorsal striatum in NQ and NS animals sensitized to nicotine. Male and female Sprague-Dawley rats were neonatally treated with quinpirole (1mg/kg) or saline from postnatal days (P)1-21. Animals were given ip injections of either saline or nicotine (0.5mg/kg free base) every second day from P33 to P49 and tested on behavioral sensitization. Before each injection, animals were ip administered the α7 nAChR antagonist methyllycaconitine (MLA; 2 or 4mg/kg) or the α4β2 nAChR antagonist dihydro beta erythroidine (DhβE; 1 or 3mg/kg). Results revealed NQ enhanced nicotine sensitization that was blocked by DhβE. MLA blocked the enhanced nicotine sensitization in NQ animals, but did not block nicotine sensitization. NQ enhanced the NAcc BDNF response to nicotine which was blocked by both antagonists. In Experiment 2, NQ enhanced nicotine sensitization and enhanced α4β2, but not α7, nAChR upregulation in the NAcc. These results suggest a relationship between accumbal BDNF and α4β2 nAChRs and their role in the behavioral response to nicotine in the NQ model which has relevance to schizophrenia, a behavioral disorder with high rates of tobacco smoking.
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Affiliation(s)
- Daniel J Peterson
- Department of Psychology, East Tennessee State University, Johnson City, TN 37614, United States
| | - W Drew Gill
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - John M Dose
- Department of Psychology, St. Norbert College, De Pere, WI, 54115,United States
| | - Donald B Hoover
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - James R Pauly
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, United States
| | - Elizabeth D Cummins
- Department of Psychology, East Tennessee State University, Johnson City, TN 37614, United States
| | - Katherine C Burgess
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States
| | - Russell W Brown
- Department of Biomedical Sciences, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, United States.
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14
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Nagatomo K, Suga S, Saitoh M, Kogawa M, Kobayashi K, Yamamoto Y, Yamada K. Dopamine D1 Receptor Immunoreactivity on Fine Processes of GFAP-Positive Astrocytes in the Substantia Nigra Pars Reticulata of Adult Mouse. Front Neuroanat 2017; 11:3. [PMID: 28203148 PMCID: PMC5285371 DOI: 10.3389/fnana.2017.00003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/13/2017] [Indexed: 12/20/2022] Open
Abstract
Substantia nigra pars reticulata (SNr), the major output nucleus of the basal ganglia, receives dopamine from dendrites extending from dopaminergic neurons of the adjacent nucleus pars compacta (SNc), which is known for its selective degeneration in Parkinson's disease. As a recipient for dendritically released dopamine, the dopamine D1 receptor (D1R) is a primary candidate due to its very dense immunoreactivity in the SNr. However, the precise location of D1R remains unclear at the cellular level in the SNr except for that reported on axons/axon terminals of presumably striatal GABAergic neurons. To address this, we used D1R promotor-controlled, mVenus-expressing transgenic mice. When cells were acutely dissociated from SNr of mouse brain, prominent mVenus fluorescence was detected in fine processes of glia-like cells, but no such fluorescence was detected from neurons in the same preparation, except for the synaptic bouton-like structure on the neurons. Double immunolabeling of SNr cells dissociated from adult wild-type mice brain further revealed marked D1R immunoreactivity in the processes of glial fibrillary acidic protein (GFAP)-positive astrocytes. Such D1R imunoreactivity was significantly stronger in the SNr astrocytes than that in those of the visual cortex in the same preparation. Interestingly, GFAP-positive astrocytes dissociated from the striatum demonstrated D1R immunoreactivity, either remarkable or minimal, similarly to that shown in neurons in this nucleus. In contrast, in the SNr and visual cortex, only weak D1R immunoreactivity was detected in the neurons tested. These results suggest that the SNr astrocyte may be a candidate recipient for dendritically released dopamine. Further study is required to fully elucidate the physiological roles of divergent dopamine receptor immunoreactivity profiles in GFAP-positive astrocytes.
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Affiliation(s)
- Katsuhiro Nagatomo
- Department of Physiology, Hirosaki University Graduate School of Medicine Aomori, Japan
| | - Sechiko Suga
- Department of Physiology, Hirosaki University Graduate School of MedicineAomori, Japan; Department of Emergency Medical Technology, Hirosaki University of Health and WelfareAomori, Japan
| | - Masato Saitoh
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University Iwate, Japan
| | - Masahito Kogawa
- Department of Physiology, Hirosaki University Graduate School of Medicine Aomori, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine Fukushima, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University Iwate, Japan
| | - Katsuya Yamada
- Department of Physiology, Hirosaki University Graduate School of Medicine Aomori, Japan
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15
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Elgueta D, Aymerich MS, Contreras F, Montoya A, Celorrio M, Rojo-Bustamante E, Riquelme E, González H, Vásquez M, Franco R, Pacheco R. Pharmacologic antagonism of dopamine receptor D3 attenuates neurodegeneration and motor impairment in a mouse model of Parkinson's disease. Neuropharmacology 2016; 113:110-123. [PMID: 27693549 DOI: 10.1016/j.neuropharm.2016.09.028] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 08/25/2016] [Accepted: 09/27/2016] [Indexed: 12/16/2022]
Abstract
Neuroinflammation involves the activation of glial cells, which is associated to the progression of neurodegeneration in Parkinson's disease. Recently, we and other researchers demonstrated that dopamine receptor D3 (D3R)-deficient mice are completely refractory to neuroinflammation and consequent neurodegeneration associated to the acute intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In this study we examined the therapeutic potential and underlying mechanism of a D3R-selective antagonist, PG01037, in mice intoxicated with a chronic regime of administration of MPTP and probenecid (MPTPp). Biodistribution analysis indicated that intraperitoneally administered PG01037 crosses the blood-brain barrier and reaches the highest concentration in the brain 40 min after the injection. Furthermore, the drug was preferentially distributed to the brain in comparison to the plasma. Treatment of MPTPp-intoxicated mice with PG01037 (30 mg/kg, administrated twice a week for five weeks) attenuated the loss of dopaminergic neurons in the substantia nigra pars compacta, as evaluated by stereological analysis, and the loss of striatal dopaminergic terminals, as determined by densitometric analyses of tyrosine hydroxylase and dopamine transporter immunoreactivities. Accordingly, the treatment resulted in significant improvement of motor performance of injured animals. Interestingly, the therapeutic dose of PG01037 exacerbated astrogliosis and resulted in increased ramification density of microglial cells in the striatum of MPTPp-intoxicated mice. Further analyses suggested that D3R expressed in astrocytes favours a beneficial astrogliosis with anti-inflammatory consequences on microglia. Our findings indicate that D3R-antagonism exerts a therapeutic effect in parkinsonian animals by reducing the loss of dopaminergic neurons in the nigrostriatal pathway, alleviating motor impairments and modifying the pro-inflammatory phenotype of glial cells.
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Affiliation(s)
- Daniela Elgueta
- Fundación Ciencia & Vida, Ñuñoa, Santiago 7780272, Chile; Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago 8370146, Chile
| | - María S Aymerich
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona 31008, Spain; Department of Biochemistry and Genetics, School of Science, University of Navarra, Pamplona 31008, Spain; IdiSNA, Navarra Institute for Health Research, Pamplona, 31008, Spain
| | | | - Andro Montoya
- Fundación Ciencia & Vida, Ñuñoa, Santiago 7780272, Chile
| | - Marta Celorrio
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona 31008, Spain
| | - Estefanía Rojo-Bustamante
- Division of Neurosciences, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona 31008, Spain; Department of Biochemistry and Genetics, School of Science, University of Navarra, Pamplona 31008, Spain
| | | | - Hugo González
- Fundación Ciencia & Vida, Ñuñoa, Santiago 7780272, Chile
| | - Mónica Vásquez
- Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago, Chile
| | - Rafael Franco
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona 08028, Spain; CIBERNED. Centro de Investigación en Red. Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, 28049, Madrid, Spain
| | - Rodrigo Pacheco
- Fundación Ciencia & Vida, Ñuñoa, Santiago 7780272, Chile; Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago 8370146, Chile.
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16
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Zhang K, Chen C, Yang Z, He W, Liao X, Ma Q, Deng P, Lu J, Li J, Wang M, Li M, Zheng L, Zhou Z, Sun W, Wang L, Jia H, Yu Z, Zhou Z, Chen X. Sensory Response of Transplanted Astrocytes in Adult Mammalian Cortex In Vivo. Cereb Cortex 2016; 26:3690-3704. [PMID: 27405333 PMCID: PMC5004757 DOI: 10.1093/cercor/bhw213] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 06/13/2016] [Indexed: 12/16/2022] Open
Abstract
Glial precursor transplantation provides a potential therapy for brain disorders. Before its clinical application, experimental evidence needs to indicate that engrafted glial cells are functionally incorporated into the existing circuits and become essential partners of neurons for executing fundamental brain functions. While previous experiments supporting for their functional integration have been obtained under in vitro conditions using slice preparations, in vivo evidence for such integration is still lacking. Here, we utilized in vivo two-photon Ca2+ imaging along with immunohistochemistry, fluorescent indicator labeling-based axon tracing and correlated light/electron microscopy to analyze the profiles and the functional status of glial precursor cell-derived astrocytes in adult mouse neocortex. We show that after being transplanted into somatosensory cortex, precursor-derived astrocytes are able to survive for more than a year and respond with Ca2+ signals to sensory stimulation. These sensory-evoked responses are mediated by functionally-expressed nicotinic receptors and newly-established synaptic contacts with the host cholinergic afferents. Our results provide in vivo evidence for a functional integration of transplanted astrocytes into adult mammalian neocortex, representing a proof-of-principle for sensory cortex remodeling through addition of essential neural elements. Moreover, we provide strong support for the use of glial precursor transplantation to understand glia-related neural development in vivo.
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Affiliation(s)
- Kuan Zhang
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Chunhai Chen
- Department of Occupational Health, Third Military Medical University, Chongqing 400038, China
| | - Zhiqi Yang
- Brain Research Center, Third Military Medical University, Chongqing 400038, China.,Department of Neurology, Lanzhou General Hospital, Lanzhou Military Area Command, Lanzhou, Gansu 730050, China
| | - Wenjing He
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Xiang Liao
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Qinlong Ma
- Department of Occupational Health, Third Military Medical University, Chongqing 400038, China
| | - Ping Deng
- Department of Occupational Health, Third Military Medical University, Chongqing 400038, China
| | - Jian Lu
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Jingcheng Li
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Meng Wang
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Mingli Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lianghong Zheng
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Zhuan Zhou
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Wei Sun
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Liting Wang
- Brain Research Center, Third Military Medical University, Chongqing 400038, China
| | - Hongbo Jia
- Brain Research Instrument Innovation Center, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China
| | - Zhengping Yu
- Department of Occupational Health, Third Military Medical University, Chongqing 400038, China
| | - Zhou Zhou
- Department of Occupational Health, Third Military Medical University, Chongqing 400038, China
| | - Xiaowei Chen
- Brain Research Center, Third Military Medical University, Chongqing 400038, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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17
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Astrocytes as Pharmacological Targets in the Treatment of Schizophrenia. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2016. [DOI: 10.1016/b978-0-12-800981-9.00025-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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de Kloet SF, Mansvelder HD, De Vries TJ. Cholinergic modulation of dopamine pathways through nicotinic acetylcholine receptors. Biochem Pharmacol 2015. [PMID: 26208783 DOI: 10.1016/j.bcp.2015.07.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Nicotine addiction is highly prevalent in current society and is often comorbid with other diseases. In the central nervous system, nicotine acts as an agonist for nicotinic acetylcholine receptors (nAChRs) and its effects depend on location and receptor composition. Although nicotinic receptors are found in most brain regions, many studies on addiction have focused on the mesolimbic system and its reported behavioral correlates such as reward processing and reinforcement learning. Profound modulatory cholinergic input from the pedunculopontine and laterodorsal tegmentum to dopaminergic midbrain nuclei as well as local cholinergic interneuron projections to dopamine neuron axons in the striatum may play a major role in the effects of nicotine. Moreover, an indirect mesocorticolimbic feedback loop involving the medial prefrontal cortex may be involved in behavioral characteristics of nicotine addiction. Therefore, this review will highlight current understanding of the effects of nicotine on the function of mesolimbic and mesocortical dopamine projections in the mesocorticolimbic circuit.
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Affiliation(s)
- Sybren F de Kloet
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cogntive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cogntive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands.
| | - Taco J De Vries
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cogntive Research (CNCR), Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands; Department of Anatomy and Neurosciences, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
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19
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Fuxe K, Agnati LF, Marcoli M, Borroto-Escuela DO. Volume Transmission in Central Dopamine and Noradrenaline Neurons and Its Astroglial Targets. Neurochem Res 2015; 40:2600-14. [PMID: 25894681 DOI: 10.1007/s11064-015-1574-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/16/2015] [Accepted: 04/04/2015] [Indexed: 12/11/2022]
Abstract
Already in the 1960s the architecture and pharmacology of the brainstem dopamine (DA) and noradrenaline (NA) neurons with formation of vast numbers of DA and NA terminal plexa of the central nervous system (CNS) indicated that they may not only communicate via synaptic transmission. In the 1980s the theory of volume transmission (VT) was introduced as a major communication together with synaptic transmission in the CNS. VT is an extracellular and cerebrospinal fluid transmission of chemical signals like transmitters, modulators etc. moving along energy gradients making diffusion and flow of VT signals possible. VT interacts with synaptic transmission mainly through direct receptor-receptor interactions in synaptic and extrasynaptic heteroreceptor complexes and their signaling cascades. The DA and NA neurons are specialized for extrasynaptic VT at the soma-dendrtitic and terminal level. The catecholamines released target multiple DA and adrenergic subtypes on nerve cells, astroglia and microglia which are the major cell components of the trophic units building up the neural-glial networks of the CNS. DA and NA VT can modulate not only the strength of synaptic transmission but also the VT signaling of the astroglia and microglia of high relevance for neuron-glia interactions. The catecholamine VT targeting astroglia can modulate the fundamental functions of astroglia observed in neuroenergetics, in the Glymphatic system, in the central renin-angiotensin system and in the production of long-distance calcium waves. Also the astrocytic and microglial DA and adrenergic receptor subtypes mediating DA and NA VT can be significant drug targets in neurological and psychiatric disease.
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Affiliation(s)
- Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, 17177, Stockholm, Sweden.
| | - Luigi F Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, 41100, Modena, Italy
| | - Manuela Marcoli
- Dipartimento di Farmacia, Sezione di Farmacologia e Tossicologia, Università di Genova, Viale Cembrano 4, 16148, Genoa, Italy.,Center of Excellence for Biomedical Research, Università di Genova, Viale Benedetto XV 5, 16132, Genoa, Italy
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20
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Malkusz DC, Yenko I, Rotella FM, Banakos T, Olsson K, Dindyal T, Vig V, Bodnar RJ. Dopamine receptor signaling in the medial orbital frontal cortex and the acquisition and expression of fructose-conditioned flavor preferences in rats. Brain Res 2014; 1596:116-25. [PMID: 25446441 DOI: 10.1016/j.brainres.2014.11.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 11/16/2022]
Abstract
Systemic dopamine (DA) D1 (SCH23390: SCH) and D2 (raclopride: RAC) antagonists blocked fructose-conditioned flavor preference (CFP) acquisition and expression. Fructose-CFP acquisition was eliminated by medial prefrontal cortex (mPFC) SCH and mPFC or amygdala (AMY) RAC. Fructose-CFP expression was reduced following SCH or RAC in AMY or nucleus accumbens (NAc). The present study examined fructose-CFP acquisition and expression following SCH and RAC in the medial orbital frontal cortex (MOFC), another ventral tegmental area DA target. For fructose-CFP acquisition, five groups of rats received vehicle, SCH (24 or 48 nmol) or RAC (24 or 48 nmol) in the MOFC 0.5h prior to 8 training sessions with one flavor (CS+/Fs) mixed in 8% fructose and 0.2% saccharin, and another flavor (CS-/s) mixed in 0.2% saccharin. In six 2-bottle choice tests in 0.2% saccharin, similar fructose-CFP preferences occurred in groups trained with vehicle (76-77%), SCH24 (69-78%), SCH48 (70-74%) and RAC48 (85-92%). RAC24-trained rats displayed significant CS+ preferences during the first (79%) and third (71%), but not second (58%) test pair. For fructose-CFP expression, rats similarly trained with CS+/Fs and CS- solutions received 2-bottle choice tests following MOFC injections of SCH or RAC (12-48 nmol). CS+ preference expression was significantly reduced by RAC (48 nmol: 58%), but not SCH relative to vehicle (78%). A control group receiving RAC in the dorsolateral prefrontal cortex displayed fructose-CFP expression similar to vehicle. These data demonstrate differential frontal cortical DA mediation of fructose-CFP with mPFC D1 and D2 signaling exclusively mediating acquisition, and MOFC D2 signaling primarily mediating expression.
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Affiliation(s)
- Danielle C Malkusz
- Behavioral and Cognitive Neuroscience Cluster, Psychology Doctoral Program, The Graduate Center, City University of New York, New York, NY, United States
| | - Ira Yenko
- Department of Psychology, Queens College, City University of New York, New York, NY, United States
| | - Francis M Rotella
- Behavioral and Cognitive Neuroscience Cluster, Psychology Doctoral Program, The Graduate Center, City University of New York, New York, NY, United States
| | - Theodore Banakos
- Department of Psychology, Queens College, City University of New York, New York, NY, United States
| | - Kerstin Olsson
- Department of Psychology, Queens College, City University of New York, New York, NY, United States
| | - Trisha Dindyal
- Department of Psychology, Queens College, City University of New York, New York, NY, United States
| | - Vishal Vig
- Department of Psychology, Queens College, City University of New York, New York, NY, United States
| | - Richard J Bodnar
- Behavioral and Cognitive Neuroscience Cluster, Psychology Doctoral Program, The Graduate Center, City University of New York, New York, NY, United States; Department of Psychology, Queens College, City University of New York, New York, NY, United States.
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21
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Beggiato S, Tanganelli S, Fuxe K, Antonelli T, Schwarcz R, Ferraro L. Endogenous kynurenic acid regulates extracellular GABA levels in the rat prefrontal cortex. Neuropharmacology 2014; 82:11-8. [PMID: 24607890 DOI: 10.1016/j.neuropharm.2014.02.019] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/07/2014] [Accepted: 02/25/2014] [Indexed: 12/17/2022]
Abstract
The tryptophan metabolite kynurenic acid (KYNA) is an endogenous antagonist of the α7 nicotinic acetylcholine receptor (α7nAChR) and, at higher concentrations, inhibits ionotropic glutamate receptors. Increases in KYNA levels are seen in brain and cerebrospinal fluid in individuals with schizophrenia (SZ) and may be causally related to cognitive deficits in SZ and other psychiatric diseases. As dysfunction of circuits involving GABAergic neurons in the prefrontal cortex (PFC) likely plays a role in the cognitive impairments seen in these disorders, we examined the effects of KYNA on extracellular GABA in this brain area. Applied to awake rats for 2 h by reverse dialysis, KYNA concentration-dependently and reversibly reduced extracellular GABA levels, with 300 nM KYNA causing a nadir of ∼45% of baseline concentrations. This effect was not duplicated by reverse dialysis of the selective glycineB receptor antagonist 7-Cl-KYNA (100 nM) or the AMPA/kainate receptor antagonist CNQX (100 μM), and was prevented by co-application of galantamine (5 μM), a positive allosteric modulator of the α7nAChR. Conversely, inhibition of endogenous KYNA formation by reverse dialysis of (S)-4-(ethylsulfonyl)benzoylalanine (ESBA; 5 mM) reversibly increased GABA levels in the PFC, reaching a peak of ∼160% of baseline concentrations. Co-infusion of 30 nM KYNA neutralized this effect. Taken together, these results demonstrate a role for endogenous KYNA in the bi-directional control of GABAergic neurotransmission in the PFC. Pharmacological manipulation of KYNA may therefore be useful in the treatment of GABAergic impairments in SZ and other brain disorders involving the PFC.
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Affiliation(s)
- Sarah Beggiato
- Department of Medical Sciences, University of Ferrara, Italy; Laboratory for the Technology of Advanced Therapies (LTTA Centre), University of Ferrara, Italy.
| | - Sergio Tanganelli
- Department of Medical Sciences, University of Ferrara, Italy; Laboratory for the Technology of Advanced Therapies (LTTA Centre), University of Ferrara, Italy
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Tiziana Antonelli
- Department of Medical Sciences, University of Ferrara, Italy; Laboratory for the Technology of Advanced Therapies (LTTA Centre), University of Ferrara, Italy
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Luca Ferraro
- Laboratory for the Technology of Advanced Therapies (LTTA Centre), University of Ferrara, Italy; Department of Life Sciences and Biotechnology, University of Ferrara, Italy
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Garzón M, Duffy AM, Chan J, Lynch MK, Mackie K, Pickel VM. Dopamine D₂ and acetylcholine α7 nicotinic receptors have subcellular distributions favoring mediation of convergent signaling in the mouse ventral tegmental area. Neuroscience 2013; 252:126-43. [PMID: 23954803 DOI: 10.1016/j.neuroscience.2013.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 08/06/2013] [Accepted: 08/06/2013] [Indexed: 11/24/2022]
Abstract
Alpha7 nicotinic acetylcholine receptors (α7nAChRs) mediate nicotine-induced burst-firing of dopamine neurons in the ventral tegmental area (VTA), a limbic brain region critically involved in reward and in dopamine D2 receptor (D2R)-related cortical dysfunctions associated with psychosis. The known presence of α7nAChRs and Gi-coupled D2Rs in dopamine neurons of the VTA suggests that these receptors are targeted to at least some of the same neurons in this brain region. To test this hypothesis, we used electron microscopic immunolabeling of antisera against peptide sequences of α7nACh and D2 receptors in the mouse VTA. Dual D2R and α7nAChR labeling was seen in many of the same somata (co-localization over 97%) and dendrites (co-localization over 49%), where immunoreactivity for each of the receptors was localized to endomembranes as well as to non-synaptic or synaptic plasma membranes often near excitatory-type synapses. In comparison with somata and dendrites, many more small axons and axon terminals were separately labeled for each of the receptors. Thus, single-labeled axon terminals were predominant for both α7nAChR (57.9%) and D2R (89.0%). The majority of the immunolabeled axonal profiles contained D2R-immunoreactivity (81.6%) and formed either symmetric or asymmetric synapses consistent with involvement in the release of both inhibitory and excitatory transmitters. Of 160 D2R-labeled terminals, 81.2% were presynaptic to dendrites that expressed α7nAChR alone or together with the D2R. Numerous glial processes inclusive of those enveloping either excitatory- or inhibitory-type synapses also contained single labeling for D2R (n=152) and α7nAChR (n=561). These results suggest that classic antipsychotic drugs, all of which block the D2R, may facilitate α7nAChR-mediated burst-firing by elimination of D2R-dependent inhibition in neurons expressing both receptors as well as by indirect pre-synaptic and glial mechanisms.
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Affiliation(s)
- M Garzón
- Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065, USA; Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina UAM, Madrid 28029, Spain; Instituto de Investigación Hospital Universitario La Paz (IDIPAZ), Paseo de la Castellana 261, Madrid 28046, Spain
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23
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Barzilai A. The interrelations between malfunctioning DNA damage response (DDR) and the functionality of the neuro-glio-vascular unit. DNA Repair (Amst) 2013; 12:543-57. [DOI: 10.1016/j.dnarep.2013.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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24
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Scarr E, Gibbons AS, Neo J, Udawela M, Dean B. Cholinergic connectivity: it's implications for psychiatric disorders. Front Cell Neurosci 2013; 7:55. [PMID: 23653591 PMCID: PMC3642390 DOI: 10.3389/fncel.2013.00055] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 04/12/2013] [Indexed: 01/01/2023] Open
Abstract
Acetylcholine has been implicated in both the pathophysiology and treatment of a number of psychiatric disorders, with most of the data related to its role and therapeutic potential focusing on schizophrenia. However, there is little thought given to the consequences of the documented changes in the cholinergic system and how they may affect the functioning of the brain. This review looks at the cholinergic system and its interactions with the intrinsic neurotransmitters glutamate and gamma-amino butyric acid as well as those with the projection neurotransmitters most implicated in the pathophysiologies of psychiatric disorders; dopamine and serotonin. In addition, with the recent focus on the role of factors normally associated with inflammation in the pathophysiologies of psychiatric disorders, links between the cholinergic system and these factors will also be examined. These interfaces are put into context, primarily for schizophrenia, by looking at the changes in each of these systems in the disorder and exploring, theoretically, whether the changes are interconnected with those seen in the cholinergic system. Thus, this review will provide a comprehensive overview of the connectivity between the cholinergic system and some of the major areas of research into the pathophysiologies of psychiatric disorders, resulting in a critical appraisal of the potential outcomes of a dysregulated central cholinergic system.
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Affiliation(s)
- Elizabeth Scarr
- Department of Psychiatry, The University of MelbourneParkville, VIC, Australia
- Molecular Psychiatry Laboratories, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
| | - Andrew S. Gibbons
- Department of Psychiatry, The University of MelbourneParkville, VIC, Australia
- Molecular Psychiatry Laboratories, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
| | - Jaclyn Neo
- Department of Psychiatry, The University of MelbourneParkville, VIC, Australia
- Molecular Psychiatry Laboratories, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
| | - Madhara Udawela
- Molecular Psychiatry Laboratories, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
- Centre for Neuroscience, The University of MelbourneParkville, VIC, Australia
| | - Brian Dean
- Department of Psychiatry, The University of MelbourneParkville, VIC, Australia
- Molecular Psychiatry Laboratories, Florey Institute of Neuroscience and Mental HealthParkville, VIC, Australia
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25
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Beggiato S, Antonelli T, Tomasini MC, Tanganelli S, Fuxe K, Schwarcz R, Ferraro L. Kynurenic acid, by targeting α7 nicotinic acetylcholine receptors, modulates extracellular GABA levels in the rat striatum in vivo. Eur J Neurosci 2013; 37:1470-7. [PMID: 23442092 DOI: 10.1111/ejn.12160] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/14/2013] [Accepted: 01/17/2013] [Indexed: 01/02/2023]
Abstract
Kynurenic acid (KYNA) is an astrocyte-derived non-competitive antagonist of the α7 nicotinic acetylcholine receptor (α7nAChR) and inhibits the NMDA receptor (NMDAR) competitively. The main aim of the present study was to examine the possible effects of KYNA (30 - 1000 nm), applied locally by reverse dialysis for 2 h, on extracellular GABA levels in the rat striatum. KYNA concentration-dependently reduced GABA levels, with 300 nm KYNA causing a maximal reduction to ~60% of baseline concentrations. The effect of KYNA (100 nm) was prevented by co-application of galantamine (5 μm), an agonist at a site of the α7nAChR that is very similar to that targeted by KYNA. Infusion of 7-chlorokynurenic acid (100 nm), an NMDAR antagonist acting selectively at the glycineB site of the receptor, affected neither basal GABA levels nor the KYNA-induced reduction in GABA. Inhibition of endogenous KYNA formation by reverse dialysis of (S)-4-(ethylsulfonyl)benzoylalanine (ESBA; 1 mm) increased extracellular GABA levels, reaching a peak of 156% of baseline levels after 1 h. Co-infusion of 100 nm KYNA abolished the effect of ESBA. Qualitatively and quantitatively similar, bi-directional effects of KYNA on extracellular glutamate were observed in the same microdialysis samples. Taken together, the present findings suggest that fluctuations in endogenous KYNA levels, by modulating α7nAChR function, control extracellular GABA levels in the rat striatum. This effect may be relevant for a number of physiological and pathological processes involving the basal ganglia.
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Affiliation(s)
- Sarah Beggiato
- Department of Medical Sciences, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy.
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26
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Fitzgerald ML, Mackie K, Pickel VM. The impact of adolescent social isolation on dopamine D2 and cannabinoid CB1 receptors in the adult rat prefrontal cortex. Neuroscience 2013; 235:40-50. [PMID: 23333674 DOI: 10.1016/j.neuroscience.2013.01.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/02/2013] [Accepted: 01/03/2013] [Indexed: 12/11/2022]
Abstract
Adolescent experiences of social deprivation result in profound and enduring perturbations in adult behavior, including impaired sensorimotor gating. The behavioral deficits induced by adolescent social isolation in rats can be ameliorated by antipsychotic drugs blocking dopamine D2 receptors in the prefrontal cortex (PFC) or by chronic administration of a cannabinoid CB1 receptor antagonist. The patterning and abundance of D2 receptors in the PFC evolves concurrently with CB1 receptors through the period of adolescence. This evidence suggests that mature expression and/or surface distribution of D2 and CB1 receptors may be influenced by the adolescent social environment. We tested this hypothesis using electron microscopic immunolabeling to compare the distribution of CB1 and D2 receptors in the PFC of adult male Sprague-Dawley rats that were isolated or socially reared throughout the adolescent transition period. Prepulse inhibition (PPI) of acoustic startle was assessed as a measure of sensorimotor gating. Social isolation reduced PPI and selectively decreased dendritic D2 immunogold labeling in the PFC. However, the decrease was only evident in dendrites that were not contacted by axon terminals containing CB1. There was no apparent change in the expression of CB1 or D2 receptors in presynaptic terminals. The D2 deficit therefore may be tempered by local CB1-mediated retrograde signaling. This suggests a biological mechanism whereby the adolescent social environment can persistently influence cortical dopaminergic activity and resultant behavior.
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Affiliation(s)
- M L Fitzgerald
- Department of Neuroscience, Brain and Mind Research Institute, Weill Cornell Medical College, 407 East 61st Street, New York, NY 10065, United States
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27
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Nordman JC, Kabbani N. An interaction between α7 nicotinic receptors and a G-protein pathway complex regulates neurite growth in neural cells. J Cell Sci 2012; 125:5502-13. [PMID: 22956546 DOI: 10.1242/jcs.110379] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The α7 acetylcholine nicotinic receptor (α7) is an important mediator of cholinergic transmission during brain development. Here we present an intracellular signaling mechanism for the α7 receptor. Proteomic analysis of immunoprecipitated α7 subunits reveals an interaction with a G protein pathway complex (GPC) comprising Gα(i/o), GAP-43 and G protein regulated inducer of neurite outgrowth 1 (Gprin1) in differentiating cells. Morphological studies indicate that α7 receptors regulate neurite length and complexity via a Gprin1-dependent mechanism that directs the expression of α7 to the cell surface. α7-GPC interactions were confirmed in embryonic cortical neurons and were found to modulate the growth of axons. Taken together, these findings reveal a novel intracellular pathway of signaling for α7 within neurons, and suggest a role for its interactions with the GPC in brain development.
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Affiliation(s)
- Jacob C Nordman
- Department of Molecular Neuroscience, Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia 22030, USA
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