1
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Hamidovic A, Cho S, Davis J. Positive association between dehydroepiandrosterone (DHEA) and gene expression of the gamma-aminobutyric acid (GABA-A) receptor δ subunit. J Steroid Biochem Mol Biol 2024; 241:106525. [PMID: 38636682 DOI: 10.1016/j.jsbmb.2024.106525] [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: 03/20/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/20/2024]
Abstract
Gamma-aminobutyric acid A (GABA-A) receptors in the cells of the immune system enhance anti-inflammatory responses by regulating cytokine secretion, cytotoxic responses, and cell activation. In the CNS, the formation of GABA-A subunits into a pentameric structure has been extensively studied; however, no such study has been conducted in the immune system. The objective of the present study was to examine associations between the levels of steroid hormones and GABA-A receptor δ subunit expression in the immune system. We focused on this subunit because GABA-A receptors that contain it become significantly more sensitive to steroid hormones. We collected 80 blood samples from reproductive age women for the purpose of analyzing dehydroepiandrosterone (DHEA), 17β-estradiol, progesterone, and allopregnanolone using liquid chromatography-mass spectrometry (LC-MS). Furthermore, we extracted peripheral blood mononuclear cells (PBMCs) for determining mRNA expression levels of GABA-A receptor genes encoding the δ and ε subunits. We constructed linear mixed effect models for each GABA-A receptor subunit with all 4 steroid hormones, age, and age of menarche as predictors. Whereas DHEA was significantly associated with δ subunit expression (t-value = 2.981; p = 0.003), in line with our hypothesis, none of the steroid hormones were significantly associated with the expression of the ε subunit. Results of this study indicate that significant interactions between hormones from the steroid hormone biosynthesis pathway and GABAergic machinery from the immune cells may be utilized to expand models examining the molecular basis of inflammatory conditions.
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Affiliation(s)
- Ajna Hamidovic
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA.
| | - Soojeong Cho
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - John Davis
- Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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2
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Li N, Tao W, Yang L, Spain WJ, Ransom CB. GABA-B receptors enhance GABA-A receptor currents by modulation of membrane trafficking in dentate gyrus granule cells. Neurosci Lett 2022; 773:136481. [DOI: 10.1016/j.neulet.2022.136481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 11/24/2022]
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3
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Wu K, Han W, Tian Q, Li Y, Lu W. Activity- and sleep-dependent regulation of tonic inhibition by Shisa7. Cell Rep 2021; 34:108899. [PMID: 33761345 PMCID: PMC8025742 DOI: 10.1016/j.celrep.2021.108899] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 12/22/2020] [Accepted: 03/03/2021] [Indexed: 02/08/2023] Open
Abstract
Tonic inhibition mediated by extrasynaptic γ-aminobutyric acid type A receptors (GABAARs) critically regulates neuronal excitability and brain function. However, the mechanisms regulating tonic inhibition remain poorly understood. Here, we report that Shisa7 is critical for tonic inhibition regulation in hippocampal neurons. In juvenile Shisa7 knockout (KO) mice, α5-GABAAR-mediated tonic currents are significantly reduced. Mechanistically, Shisa7 is crucial for α5-GABAAR exocytosis. Additionally, Shisa7 regulation of tonic inhibition requires protein kinase A (PKA) that phosphorylates Shisa7 serine 405 (S405). Importantly, tonic inhibition undergoes activity-dependent regulation, and Shisa7 is required for homeostatic potentiation of tonic inhibition. Interestingly, in young adult Shisa7 KOs, basal tonic inhibition in hippocampal neurons is unaltered, largely due to the diminished α5-GABAAR component of tonic inhibition. However, at this stage, tonic inhibition oscillates during the daily sleep/wake cycle, a process requiring Shisa7. Together, these data demonstrate that intricate signaling mechanisms regulate tonic inhibition at different developmental stages and reveal a molecular link between sleep and tonic inhibition.
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Affiliation(s)
- Kunwei Wu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wenyan Han
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qingjun Tian
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yan Li
- Proteomics Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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Dalby NO, Falk-Petersen CB, Leurs U, Scholze P, Krall J, Frølund B, Wellendorph P. Silencing of spontaneous activity at α4β1/3δ GABA A receptors in hippocampal granule cells reveals different ligand pharmacology. Br J Pharmacol 2020; 177:3975-3990. [PMID: 32484592 DOI: 10.1111/bph.15146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 05/10/2020] [Accepted: 05/14/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The δ-subunit-containing GABAA receptors, α4 β1 δ and α4 β3 δ, in dentate gyrus granule cells (DGGCs) are known to exhibit both spontaneous channel openings (i.e. constitutive activity) and agonist-induced current. The functional implications of spontaneous gating are unclear. In this study, we tested the hypothesis that constitutively active α4 β1/3 δ receptors limit agonist efficacy. EXPERIMENTAL APPROACH Whole-cell electrophysiological recordings of adult male rat and mouse hippocampal DGGCs were used to characterize known agonists and antagonists at δ-subunit-containing GABAA receptors. To separate constitutive and agonist-induced currents, different recording conditions were employed. KEY RESULTS Recordings at either 24°C or 34°C, including the PKC autoinhibitory peptide (19-36) intracellularly, removed spontaneous gating by GABAA receptors. In the absence of spontaneous gating, DGGCs responded to the α4 β1/3 δ orthosteric agonist Thio-THIP with a four-fold increased efficacy relative to recording conditions favouring constitutive activity. Surprisingly, the neutral antagonist gabazine was unable to antagonize the current by Thio-THIP. Furthermore, a current was elicited by gabazine alone only when the constitutive current was silenced (EC50 2.1 μM). The gabazine-induced current was inhibited by picrotoxin, potentiated by DS2, completely absent in δ-/- mice and reduced in β1 -/- mice, but could not be replicated in human α4 β1/3 δ receptors expressed heterologously in HEK cells. CONCLUSION AND IMPLICATIONS Kinase activity infers spontaneous gating in α4 β1/3 δ receptors in DGGCs. This significantly limits the efficacy of GABAA agonists and has implications in pathologies involving aberrant excitability caused by phosphorylation (e.g. addiction and epilepsy). In such cases, the efficacy of δ-preferring GABAA ligands may be reduced.
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Affiliation(s)
- Nils Ole Dalby
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Ulrike Leurs
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petra Scholze
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Petrine Wellendorph
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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5
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Charsouei S, Jabalameli MR, Karimi-Moghadam A. Molecular insights into the role of AMPA receptors in the synaptic plasticity, pathogenesis and treatment of epilepsy: therapeutic potentials of perampanel and antisense oligonucleotide (ASO) technology. Acta Neurol Belg 2020; 120:531-544. [PMID: 32152997 DOI: 10.1007/s13760-020-01318-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
Abstract
Glutamate is considered as the predominant excitatory neurotransmitter in the mammalian central nervous systems (CNS). Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are the main glutamate-gated ionotropic channels that mediate the majority of fast synaptic excitation in the brain. AMPARs are highly dynamic that constitutively move into and out of the postsynaptic membrane. Changes in the postsynaptic number of AMPARs play a key role in controlling synaptic plasticity and also brain functions such as memory formation and forgetting development. Impairments in the regulation of AMPAR function, trafficking, and signaling pathway may also contribute to neuronal hyperexcitability and epileptogenesis process, which offers AMPAR as a potential target for epilepsy therapy. Over the last decade, various types of AMPAR antagonists such as perampanel and talampanel have been developed to treat epilepsy, but they usually show limited efficacy at low doses and produce unwanted cognitive and motor side effects when administered at higher doses. In the present article, the latest findings in the field of molecular mechanisms controlling AMPAR biology, as well as the role of these mechanism dysfunctions in generating epilepsy will be reviewed. Also, a comprehensive summary of recent findings from clinical trials with perampanel, in treating epilepsy, glioma-associated epilepsy and Parkinson's disease is provided. Finally, antisense oligonucleotide therapy as an alternative strategy for the efficient treatment of epilepsy is discussed.
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Affiliation(s)
- Saeid Charsouei
- Department of Neurology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, IR, Iran
| | - M Reza Jabalameli
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Avenue, Bronx, NY, 10461, USA
| | - Amin Karimi-Moghadam
- Division of Genetics, Department of Biology, Faculty of Science, University of Isfahan, Isfahan, IR, Iran.
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6
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Calcium-dependent kinases in the brain have site-specific associations with locomotion and rearing impairments in rats with bile duct ligation. Behav Brain Res 2019; 372:112009. [DOI: 10.1016/j.bbr.2019.112009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/15/2019] [Accepted: 06/03/2019] [Indexed: 12/31/2022]
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7
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O'Neill N, Sylantyev S. The Functional Role of Spontaneously Opening GABA A Receptors in Neural Transmission. Front Mol Neurosci 2019; 12:72. [PMID: 30983968 PMCID: PMC6447609 DOI: 10.3389/fnmol.2019.00072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/08/2019] [Indexed: 12/22/2022] Open
Abstract
Ionotropic type of γ-aminobutyric acid receptors (GABAARs) produce two forms of inhibitory signaling: phasic inhibition generated by rapid efflux of neurotransmitter GABA into the synaptic cleft with subsequent binding to GABAARs, and tonic inhibition generated by persistent activation of extrasynaptic and/or perisynaptic GABAARs by GABA continuously present in the extracellular space. It is widely accepted that phasic and tonic GABAergic inhibition is mediated by receptor groups of distinct subunit composition and modulated by different cytoplasmic mechanisms. Recently, however, it has been demonstrated that spontaneously opening GABAARs (s-GABAARs), which do not need GABA binding to enter an active state, make a significant input into tonic inhibitory signaling. Due to GABA-independent action mode, s-GABAARs promise new safer options for therapy of neural disorders (such as epilepsy) devoid of side effects connected to abnormal fluctuations of GABA concentration in the brain. However, despite the potentially important role of s-GABAARs in neural signaling, they still remain out of focus of neuroscience studies, to a large extent due to technical difficulties in their experimental research. Here, we summarize present data on s-GABAARs functional properties and experimental approaches that allow isolation of s-GABAARs effects from those of conventional (GABA-dependent) GABAARs.
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Affiliation(s)
- Nathanael O'Neill
- Center for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Sergiy Sylantyev
- Center for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
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8
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Szodorai E, Bampali K, Romanov RA, Kasper S, Hökfelt T, Ernst M, Lubec G, Harkany T. Diversity matters: combinatorial information coding by GABA A receptor subunits during spatial learning and its allosteric modulation. Cell Signal 2018; 50:142-159. [DOI: 10.1016/j.cellsig.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/08/2018] [Accepted: 07/09/2018] [Indexed: 01/11/2023]
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9
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Moine H, Vitale N. Of local translation control and lipid signaling in neurons. Adv Biol Regul 2018; 71:194-205. [PMID: 30262213 DOI: 10.1016/j.jbior.2018.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/12/2018] [Accepted: 09/12/2018] [Indexed: 12/12/2022]
Abstract
Fine-tuned regulation of new proteins synthesis is key to the fast adaptation of cells to their changing environment and their response to external cues. Protein synthesis regulation is particularly refined and important in the case of highly polarized cells like neurons where translation occurs in the subcellular dendritic compartment to produce long-lasting changes that enable the formation, strengthening and weakening of inter-neuronal connection, constituting synaptic plasticity. The changes in local synaptic proteome of neurons underlie several aspects of synaptic plasticity and new protein synthesis is necessary for long-term memory formation. Details of how neuronal translation is locally controlled only start to be unraveled. A generally accepted view is that mRNAs are transported in a repressed state and are translated locally upon externally cued triggering signaling cascades that derepress or activate translation machinery at specific sites. Some important yet poorly considered intermediates in these cascades of events are signaling lipids such as diacylglycerol and its balancing partner phosphatidic acid. A link between these signaling lipids and the most common inherited cause of intellectual disability, Fragile X syndrome, is emphasizing the important role of these secondary messages in synaptically controlled translation.
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Affiliation(s)
- Hervé Moine
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404, Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404, Illkirch, France; Université de Strasbourg, 67084, Strasbourg, France.
| | - Nicolas Vitale
- Université de Strasbourg, 67084, Strasbourg, France; Institut des Neurosciences Cellulaires et Intégratives, UPR3212 CNRS, 67084, Strasbourg, France
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10
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O'Neill N, Sylantyev S. Feature Article: Selective modulation of tonically active GABA A receptor functional subgroups by G-proteins and protein kinase C. Exp Biol Med (Maywood) 2018; 243:1046-1055. [PMID: 30205722 DOI: 10.1177/1535370218800980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
IMPACT STATEMENT Here we study intracellular mechanisms which regulate inhibitory signaling delivered through continuously (tonically) open ionotropic receptors of γ-aminobutyric acid (GABA) of dentate gyrus granule cells (DGCs). We found that, apart of classical GABA-A receptors (GABAARs) which can be activated by GABA binding, a significant part of tonic inhibitory current is delivered by newly discovered spontaneously opening GABAARs (s-GABAARs), which enter active state without binding of GABA. We have also found that conventional GABAARs and s-GABAARs are regulated by different intracellular mechanisms, which may overlap and thus induce various signaling repercussions. Our results demonstrate that s-GABAARs play a key role in the mechanism that implements DGCs functional role in the brain. On top of that, since regulatory mechanisms under study are affected in a number of pathological states, our results may have broad implications for treatment of neurological disorders.
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11
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O'Neill N, Sylantyev S. Spontaneously opening GABA A receptors play a significant role in neuronal signal filtering and integration. Cell Death Dis 2018; 9:813. [PMID: 30042389 PMCID: PMC6057890 DOI: 10.1038/s41419-018-0856-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/18/2018] [Accepted: 06/25/2018] [Indexed: 11/23/2022]
Abstract
Continuous (tonic) charge transfer through ionotropic receptors of γ-aminobutyric acid (GABAARs) is an important mechanism of inhibitory signalling in the brain. The conventional view has been that tonic GABA-ergic inhibitory currents are mediated by low concentrations of ambient GABA. Recently, however, it was shown that the GABA-independent, spontaneously opening GABAARs (s-GABAARs), may contribute significantly to the tonic GABAAR current. One of the common approaches to temporal lobe epilepsy (TLE) therapy is an increase of GABA concentration in the cerebrospinal fluid to augment tonic current through GABAARs. Such an increase, however, generates multiple side effects, which impose significant limitations on the use of correspondent drugs. In contrast, activation/deactivation of s-GABAARs in a GABA-independent manner may provide a mechanism of regulation of tonic conductance without modification of extracellular GABA concentration, thus avoiding connected side effects. Although s-GABAARs have been detected in our earlier work, it is unclear whether they modulate neural signalling, or, due to their independence from the neurotransmitter, they provide just a stable background effect without much impact on neural crosstalk dynamics. Here, we focused on the causal relationship between s-GABAAR activity and signal integration in the rat's dentate gyrus granule cells to find that s-GABAARs play an important role in neural signal transduction. s-GABAARs shape the dynamics of phasic inhibitory responses, regulate the action potential generation machinery and control the coincidence detection window pertinent to excitatory input summation. Our results demonstrate that tonic inhibition delivered by s-GABAARs contributes to the key mechanisms that ensure implementation of neural signal filtering and integration, in a GABA-independent manner. This makes s-GABAAR a new and important actor in the regulation of long-term neural plasticity and a perspective target for TLE therapy.
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Affiliation(s)
- Nathanael O'Neill
- CCBS, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Sergiy Sylantyev
- CCBS, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
- DCEE, Institute of Neurology, University College London, QSH, Queen Square, London, WC1N 3BG, UK.
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12
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Chen J, He Y, Wu Y, Zhou H, Su LD, Li WN, Olsen RW, Liang J, Zhou YD, Shen Y. Single Ethanol Withdrawal Regulates Extrasynaptic δ-GABA A Receptors Via PKCδ Activation. Front Mol Neurosci 2018; 11:141. [PMID: 29755316 PMCID: PMC5932167 DOI: 10.3389/fnmol.2018.00141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 04/09/2018] [Indexed: 11/23/2022] Open
Abstract
Alcohol (ethanol, EtOH) is one of the most widely abused drugs with profound effects on brain function and behavior. GABAA receptors (GABAARs) are one of the major targets for EtOH in the brain. Temporary plastic changes in GABAARs after withdrawal from a single EtOH exposure occur both in vivo and in vitro, which may be the basis for chronic EtOH addiction, tolerance and withdrawal symptoms. Extrasynaptic δ-GABAAR endocytosis is implicated in EtOH-induced GABAAR plasticity, but the mechanisms by which the relative abundance and localization of specific GABAARs are altered by EtOH exposure and withdrawal remain unclear. In this study, we investigated the mechanisms underlying rapid regulation of extrasynaptic δ-GABAAR by a single EtOH withdrawal in cultured rat hippocampal neurons. Thirty-minutes EtOH (60 mM) exposure increased extrasynaptic tonic current (Itonic) amplitude without affecting synaptic GABAAR function in neurons. In contrast, at 30 min after withdrawal, Itonic amplitude and responsiveness to acute EtOH were both reduced. Similar results occurred in neurons with okadaic acid (OA) or phorbol 12,13-dibutyrate (PDBu) exposure. Protein kinase C (PKC) inhibition prevented the reduction of Itonic amplitude and the tolerance to acute EtOH, as well as the reduction of GABAAR-δ subunit abundance induced by a single EtOH withdrawal. Moreover, EtOH withdrawal selectively increased PKCδ level, whereas PKCδ inhibition specifically rescued the EtOH-induced alterations in GABAAR-δ subunit level and δ-GABAAR function. Together, we provided strong evidence for the important roles of PKCδ in the rapid regulation of extrasynaptic δ-GABAAR induced by a single EtOH withdrawal.
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Affiliation(s)
- Juan Chen
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yang He
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Wu
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Hang Zhou
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Li-Da Su
- Neuroscience Care Unit, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Wei-Nan Li
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Richard W Olsen
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jing Liang
- Titus Family Department of Clinical Pharmacy, USC School of Pharmacy, University of Southern California, Los Angeles, CA, United States
| | - Yu-Dong Zhou
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Shen
- Department of Neurobiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, China
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13
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Gunn BG, Baram TZ. Stress and Seizures: Space, Time and Hippocampal Circuits. Trends Neurosci 2017; 40:667-679. [PMID: 28916130 DOI: 10.1016/j.tins.2017.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 08/11/2017] [Accepted: 08/23/2017] [Indexed: 10/18/2022]
Abstract
Stress is a major trigger of seizures in people with epilepsy. Exposure to stress results in the release of several stress mediators throughout the brain, including the hippocampus, a region sensitive to stress and prone to seizures. Stress mediators interact with their respective receptors to produce distinct effects on the excitability of hippocampal neurons and networks. Crucially, these stress mediators and their actions exhibit unique spatiotemporal profiles, generating a complex combinatorial output with time- and space-dependent effects on hippocampal network excitability and seizure generation.
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Affiliation(s)
- B G Gunn
- Department of Pediatrics, University of California, Irvine, CA, USA
| | - T Z Baram
- Department of Pediatrics, University of California, Irvine, CA, USA; Department of Anatomy & Neurobiology, University of California, Irvine, CA, USA; Department of Neurology, University of California, Irvine, CA, USA.
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14
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Vien TN, Moss SJ, Davies PA. Regulating the Efficacy of Inhibition Through Trafficking of γ-Aminobutyric Acid Type A Receptors. Anesth Analg 2017; 123:1220-1227. [PMID: 27285004 DOI: 10.1213/ane.0000000000001349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Trafficking of anesthetic-sensitive receptors within the plasma membrane, or from one cellular component to another, occurs continuously. Changes in receptor trafficking have implications in altering anesthetic sensitivity. γ-Aminobutyric acid type A receptors (GABAARs) are anion-permeable ion channels and are the major class of receptor in the adult mammalian central nervous system that mediates inhibition. GABAergic signaling allows for precise synchronized firing of action potentials within brain circuits that is critical for cognition, behavior, and consciousness. This precision depends upon tightly controlled trafficking of GABAARs into the membrane. General anesthetics bind to and allosterically enhance GABAARs by prolonging the open state of the receptor and thereby altering neuronal and brain circuit activity. Subunit composition and GABAAR localization strongly influence anesthetic end points; therefore, changes in GABAAR trafficking could have significant consequences to anesthetic sensitivity. GABAARs are not static membrane structures but are in a constant state of flux between extrasynaptic and synaptic locations and are continually endocytosed and recycled from and to the membrane. Neuronal activity, posttranslational modifications, and some naturally occurring and synthetic compounds can influence the expression and trafficking of GABAARs. In this article, we review GABAARs, their trafficking, and how phosphorylation of GABAAR subunits can influence the surface expression and function of the receptor. Ultimately, alterations of GABAAR trafficking could modify anesthetic end points, both unintentionally through pathologic processes but potentially as a therapeutic target to adjust anesthetic-sensitive GABAARs.
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Affiliation(s)
- Thuy N Vien
- From the *Department of Neuroscience, Tufts University School of Medicine, Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts; and †Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
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15
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Callender J, Newton A. Conventional protein kinase C in the brain: 40 years later. Neuronal Signal 2017; 1:NS20160005. [PMID: 32714576 PMCID: PMC7373245 DOI: 10.1042/ns20160005] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/02/2017] [Accepted: 03/07/2017] [Indexed: 12/16/2022] Open
Abstract
Protein kinase C (PKC) is a family of enzymes whose members transduce a large variety of cellular signals instigated by the receptor-mediated hydrolysis of membrane phospholipids. While PKC has been widely implicated in the pathology of diseases affecting all areas of physiology including cancer, diabetes, and heart disease-it was discovered, and initially characterized, in the brain. PKC plays a key role in controlling the balance between cell survival and cell death. Its loss of function is generally associated with cancer, whereas its enhanced activity is associated with neurodegeneration. This review presents an overview of signaling by diacylglycerol (DG)-dependent PKC isozymes in the brain, and focuses on the role of the Ca2+-sensitive conventional PKC isozymes in neurodegeneration.
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Affiliation(s)
- Julia A. Callender
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0721, U.S.A
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16
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Modgil A, Parakala ML, Ackley MA, Doherty JJ, Moss SJ, Davies PA. Endogenous and synthetic neuroactive steroids evoke sustained increases in the efficacy of GABAergic inhibition via a protein kinase C-dependent mechanism. Neuropharmacology 2016; 113:314-322. [PMID: 27743930 DOI: 10.1016/j.neuropharm.2016.10.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 10/03/2016] [Accepted: 10/09/2016] [Indexed: 11/16/2022]
Abstract
The neuroactive steroid (NAS) tetrahydrodeoxycorticosterone (THDOC) increases protein kinase C (PKC) mediated phosphorylation of extrasynaptic GABAA receptor (GABAAR) subunits leading to increased surface expression of α4/β3 subunit-containing extrasynaptic GABAARs, leading to a sustained increase in GABAAR tonic current density. Whether other naturally occurring and synthetic NASs share both an allosteric and metabotropic action on GABAARs is unknown. Here, we examine the allosteric and metabotropic properties of allopregnanolone (ALLO), and synthetic NASs SGE-516 and ganaxolone. ALLO, SGE-516, and ganaxolone all allosterically enhanced prototypical synaptic and extrasynaptic recombinant GABAARs. In dentate gyrus granule cells (DGGCs) all three NASs, when applied acutely, allosterically enhanced tonic and phasic GABAergic currents. In separate experiments, slices were exposed to NASs for 15 min, and then transferred to a steroid naïve recording chamber followed by ≥ 30 min wash before tonic currents were measured. A sustained increase in tonic current was observed following exposure to ALLO, or SGE-516 and was prevented by inhibiting PKC with GF 109203X. No increase in tonic current was observed with exposure to ganaxolone. In agreement with the observations of an increased tonic current, the NASs ALLO and SGE-516 increased the phosphorylation and surface expression of the β3 subunit-containing GABAARs. Our studies demonstrate that neuroactive steroids have differential abilities to induce sustained increases in the efficacy of tonic inhibition by promoting GABAAR phosphorylation and membrane trafficking dependent on PKC activity.
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Affiliation(s)
- Amit Modgil
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA
| | - Manasa L Parakala
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA
| | | | | | - Stephen J Moss
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA; Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E6BT, United Kingdom
| | - Paul A Davies
- Tufts University School of Medicine, Department of Neuroscience, 136 Harrison Ave, Boston, MA 02111, USA.
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17
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Mele M, Leal G, Duarte CB. Role of GABAAR trafficking in the plasticity of inhibitory synapses. J Neurochem 2016; 139:997-1018. [DOI: 10.1111/jnc.13742] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Miranda Mele
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Graciano Leal
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Carlos B. Duarte
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
- Department of Life Sciences; University of Coimbra; Coimbra Portugal
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18
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Ferreira R, Brandão ML, Nobre MJ. 5-HT1A receptors of the prelimbic cortex mediate the hormonal impact on learned fear expression in high-anxious female rats. Horm Behav 2016; 84:84-96. [PMID: 27328163 DOI: 10.1016/j.yhbeh.2016.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 05/13/2016] [Accepted: 05/19/2016] [Indexed: 12/26/2022]
Abstract
Hormones highly influence female behaviors. However, research on this topic has not usually considered the variable hormonal status. The prelimbic cortex (PrL) is commonly engaged in fear learning. Connections from and to this region are known to be critical in regulating anxiety, in which serotonin (5-HT) plays a fundamental role, particularly through changes in 5-HT1A receptors functioning. Also, hormone fluctuations can greatly influence anxiety in humans and anxiety-related behavior in rodents, and this influence involves the functioning of 5-HT brain systems. The present investigation sought to determine whether fluctuations in ovarian hormones relative to the estrous cycle would influence the expression of learned fear in female rats previously selected as low- (LA) or high-anxious (HA). Furthermore, we investigate the role of the 5-HT system of the PrL, particularly the 5-HT1A receptors, as a possible modulator of estrous cycle influence on the expression of learned fear through intra-PrL microinjections of 5-HT itself or the full 5-HT1A agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propylamine)tetralin). Behavioral changes were assessed using the fear-potentiated startle (FPS) procedure. The results showed that fear intensity is associated with hormonal decay, being more accentuated during the estrus phase. This increase in fear levels was found to be negatively correlated with the expression of potentiated startle. In rats prone to anxiety and tested during the proestrus and estrus phases, 5-HT mechanisms of the PrL seem to play a regulatory role in the expression of learned fear. These results were not replicated in the LA rats. Similar but less intense results were found regarding the early and late diestrus. Our data indicate that future studies on this subject need to take into account the dissociation between low- and high-responsive females to understand how hormones affect emotional behavior.
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Affiliation(s)
- Renata Ferreira
- Departamento de Psicologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (USP), 14040-901 Ribeirão Preto, SP, Brazil; Instituto de Neurociências e Comportamento-INeC, Campus USP, 14040-901 Ribeirão Preto, SP, Brazil
| | - Marcus Lira Brandão
- Departamento de Psicologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (USP), 14040-901 Ribeirão Preto, SP, Brazil; Instituto de Neurociências e Comportamento-INeC, Campus USP, 14040-901 Ribeirão Preto, SP, Brazil
| | - Manoel Jorge Nobre
- Departamento de Psicologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo (USP), 14040-901 Ribeirão Preto, SP, Brazil; Departamento de Psicologia, Uni-FACEF, 14401-135 Franca, SP, Brazil; Instituto de Neurociências e Comportamento-INeC, Campus USP, 14040-901 Ribeirão Preto, SP, Brazil.
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19
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Werner DF, Porcu P, Boyd KN, O'Buckley TK, Carter JM, Kumar S, Morrow AL. Ethanol-induced GABAA receptor alpha4 subunit plasticity involves phosphorylation and neuroactive steroids. Mol Cell Neurosci 2016; 72:1-8. [PMID: 26805653 DOI: 10.1016/j.mcn.2016.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 12/11/2015] [Accepted: 01/09/2016] [Indexed: 10/22/2022] Open
Abstract
GABAA receptors containing α4 subunits are widely implicated in acute ethanol sensitivity, and their spatial and temporal regulation prominently contributes to ethanol-induced neuroplasticity in hippocampus and cortex. However, it is unknown if α4-containing GABAA receptors in the thalamus, an area of high α4 expression, display similar regulatory patterns following ethanol administration, and if so, by which molecular mechanisms. In the current study, thalamic GABAA receptor α4 subunit levels were increased following a 6-week-, but not a 2-week chronic ethanol diet. Following acute high-dose ethanol administration, thalamic GABAA receptor α4 subunit levels were regulated in a temporal fashion, as a decrease was observed at 2h followed by a delayed transient increase. PKCγ and PKCδ levels paralleled α4 temporal expression patterns following ethanol exposure. Initial decreases in α4 subunit expression were associated with reduced serine phosphorylation. Delayed increases in expression were not associated with a change in phosphorylation state, but were prevented by inhibiting neuroactive steroid production with the 5α-reductase inhibitor finasteride. Overall, these studies indicate that thalamic GABAA receptor α4 subunit expression following acute and chronic ethanol administration exhibits similar regulatory patterns as other regions and that transient expression patterns following acute exposure in vivo are likely dependent on both subunit phosphorylation state and neuroactive steroids.
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Affiliation(s)
- David F Werner
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA; Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, NY 13902, USA.
| | - Patrizia Porcu
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA; Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA; Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Kevin N Boyd
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA
| | - Todd K O'Buckley
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA
| | - Jenna M Carter
- Department of Psychology, Center for Development and Behavioral Neuroscience, Binghamton University - State University of New York, Binghamton, NY 13902, USA
| | - Sandeep Kumar
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA; Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA
| | - A Leslie Morrow
- Bowles Center for Alcohol Studies, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA; Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA; Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7178, USA
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20
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Bohnsack JP, Carlson SL, Morrow AL. Differential regulation of synaptic and extrasynaptic α4 GABA(A) receptor populations by protein kinase A and protein kinase C in cultured cortical neurons. Neuropharmacology 2016; 105:124-132. [PMID: 26767953 DOI: 10.1016/j.neuropharm.2016.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 12/07/2015] [Accepted: 01/04/2016] [Indexed: 11/24/2022]
Abstract
The GABAA α4 subunit exists in two distinct populations of GABAA receptors. Synaptic GABAA α4 receptors are localized at the synapse and mediate phasic inhibitory neurotransmission, while extrasynaptic GABAA receptors are located outside of the synapse and mediate tonic inhibitory transmission. These receptors have distinct pharmacological and biophysical properties that contribute to interest in how these different subtypes are regulated under physiological and pathological states. We utilized subcellular fractionation procedures to separate these populations of receptors in order to investigate their regulation by protein kinases in cortical cultured neurons. Protein kinase A (PKA) activation decreases synaptic α4 expression while protein kinase C (PKC) activation increases α4 subunit expression, and these effects are associated with increased β3 S408/409 or γ2 S327 phosphorylation respectively. In contrast, PKA activation increases extrasynaptic α4 and δ subunit expression, while PKC activation has no effect. Our findings suggest synaptic and extrasynaptic GABAA α4 subunit expression can be modulated by PKA to inform the development of more specific therapeutics for neurological diseases that involve deficits in GABAergic transmission.
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Affiliation(s)
- John Peyton Bohnsack
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7365, USA; Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599-7178, USA
| | - Stephen L Carlson
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599-7178, USA
| | - A Leslie Morrow
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7365, USA; Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7365, USA; Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill NC, 27599-7178, USA.
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21
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Garcia-Munoz M, Arbuthnott GW. Basal ganglia-thalamus and the "crowning enigma". Front Neural Circuits 2015; 9:71. [PMID: 26582979 PMCID: PMC4631818 DOI: 10.3389/fncir.2015.00071] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 10/22/2015] [Indexed: 11/13/2022] Open
Abstract
When Hubel (1982) referred to layer 1 of primary visual cortex as "… a 'crowning mystery' to keep area-17 physiologists busy for years to come …" he could have been talking about any cortical area. In the 80's and 90's there were no methods to examine this neuropile on the surface of the cortex: a tangled web of axons and dendrites from a variety of different places with unknown specificities and doubtful connections to the cortical output neurons some hundreds of microns below. Recently, three changes have made the crowning enigma less of an impossible mission: the clear presence of neurons in layer 1 (L1), the active conduction of voltage along apical dendrites and optogenetic methods that might allow us to look at one source of input at a time. For all of those reasons alone, it seems it is time to take seriously the function of L1. The functional properties of this layer will need to wait for more experiments but already L1 cells are GAD67 positive, i.e., inhibitory! They could reverse the sign of the thalamic glutamate (GLU) input for the entire cortex. It is at least possible that in the near future normal activity of individual sources of L1 could be detected using genetic tools. We are at the outset of important times in the exploration of thalamic functions and perhaps the solution to the crowning enigma is within sight. Our review looks forward to that solution from the solid basis of the anatomy of the basal ganglia output to motor thalamus. We will focus on L1, its afferents, intrinsic neurons and its influence on responses of pyramidal neurons in layers 2/3 and 5. Since L1 is present in the whole cortex we will provide a general overview considering evidence mainly from the somatosensory (S1) cortex before focusing on motor cortex.
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Affiliation(s)
| | - Gordon W Arbuthnott
- Okinawa Institute of Science and Technology Graduate University Okinawa, Japan
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22
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Carlson SL, Bohnsack JP, Patel V, Morrow AL. Regulation of Extrasynaptic GABAA α4 Receptors by Ethanol-Induced Protein Kinase A, but Not Protein Kinase C Activation in Cultured Rat Cerebral Cortical Neurons. J Pharmacol Exp Ther 2015; 356:148-56. [PMID: 26483396 DOI: 10.1124/jpet.115.228056] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/14/2015] [Indexed: 01/14/2023] Open
Abstract
Ethanol produces changes in GABAA receptor trafficking and function that contribute to ethanol dependence symptomatology. Extrasynaptic γ-aminobutyric acid A receptors (GABAA-R) mediate inhibitory tonic current and are of particular interest because they are potentiated by physiologically relevant doses of ethanol. Here, we isolate GABAA α4δ receptors by western blotting in subsynaptic fractions to investigate protein kinase A (PKA) and protein kinase C (PKC) modulation of ethanol-induced receptor trafficking, while extrasynaptic receptor function is determined by measurement of tonic inhibition and responses evoked by 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP). Rat cerebral cortical neurons were grown for 18 days in vitro and exposed to ethanol and/or PKA/PKC modulators. Ethanol exposure (1 hour) did not alter GABAA α4 receptor abundance, but it increased tonic current amplitude, an effect that was prevented by inhibiting PKA, but not PKC. Direct activation of PKA, but not PKC, increased the abundance and tonic current of extrasynaptic α4δ receptors. In contrast, prolonged ethanol exposure (4 hours) reduced α4δ receptor abundance as well as tonic current, and this effect was also PKA dependent. Finally, PKC activation by ethanol or phorbol-12,13-dibutyrate (PdBu) had no effect on extrasynaptic α4δ subunit abundance or activity. We conclude that ethanol alters extrasynaptic α4δ receptor function and expression in cortical neurons in a PKA-dependent manner, but ethanol activation of PKC does not influence these receptors. These results could have clinical relevance for therapeutic strategies to restore normal GABAergic functioning for the treatment of alcohol use disorders.
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Affiliation(s)
- Stephen L Carlson
- Bowles Center for Alcohol Studies and Departments of Psychiatry and Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - J Peyton Bohnsack
- Bowles Center for Alcohol Studies and Departments of Psychiatry and Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Vraj Patel
- Bowles Center for Alcohol Studies and Departments of Psychiatry and Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - A Leslie Morrow
- Bowles Center for Alcohol Studies and Departments of Psychiatry and Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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23
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Kudryashova IV. The plasticity of inhibitory synapses as a factor of long-term modifications. NEUROCHEM J+ 2015. [DOI: 10.1134/s1819712415030058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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Roseti C, van Vliet EA, Cifelli P, Ruffolo G, Baayen JC, Di Castro MA, Bertollini C, Limatola C, Aronica E, Vezzani A, Palma E. GABAA currents are decreased by IL-1β in epileptogenic tissue of patients with temporal lobe epilepsy: implications for ictogenesis. Neurobiol Dis 2015; 82:311-320. [PMID: 26168875 DOI: 10.1016/j.nbd.2015.07.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/02/2015] [Accepted: 07/06/2015] [Indexed: 01/01/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is the most prevalent form of adult focal onset epilepsy often associated with drug-resistant seizures. Numerous studies suggest that neuroinflammatory processes are pathologic hallmarks of both experimental and human epilepsy. In particular, the interleukin (IL)-1β/IL-1 receptor type 1 (R1) axis is activated in epileptogenic tissue, where it contributes significantly to the generation and recurrence of seizures in animal models. In this study, we investigated whether IL-1β affects the GABA-evoked currents (I(GABA)) in TLE tissue from humans. Given the limited availability of fresh human brain specimens, we used the "microtransplantation" method of injecting Xenopus oocytes with membranes from surgically resected hippocampal and cortical tissue from 21 patients with TLE and hippocampal sclerosis (HS), hippocampal tissue from five patients with TLE without HS, and autoptic and surgical brain specimens from 15 controls without epilepsy. We report the novel finding that pathophysiological concentrations of IL-1β decreased the I(GABA) amplitude by up to 30% in specimens from patients with TLE with or without HS, but not in control tissues. This effect was reproduced by patch-clamp recordings on neurons in entorhinal cortex slices from rats with chronic epilepsy, and was not observed in control slices. In TLE specimens from humans, the IL-1β effect was mediated by IL-1R1 and PKC. We also showed that IL-1R1 and IRAK1, the proximal kinase mediating the IL-1R1 signaling, are both up-regulated in the TLE compared with control specimens, thus supporting the idea that the IL-1β/IL-R1 axis is activated in human epilepsy. Our findings suggest a novel mechanism possibly underlying the ictogenic action of IL-1β, thus suggesting that this cytokine contributes to seizure generation in human TLE by reducing GABA-mediated neurotransmission.
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Affiliation(s)
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Pierangelo Cifelli
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy; Ri.MED Foundation, Palermo, Italy
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Johannes C Baayen
- Department of Neurosurgery, VU University Medical Center, Amsterdam, The Netherlands
| | - Maria Amalia Di Castro
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Cristina Bertollini
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Eleonora Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands; Stichting Epilepsie Instellingen Nederland (SEIN-Heemstede), The Netherlands
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche "Mario Negri", Milano, Italy.
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy; IRCCS San Raffaele Pisana, Rome, Italy.
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25
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García-Oscos F, Torres-Ramírez O, Dinh L, Galindo-Charles L, Pérez Padilla EA, Pineda JC, Atzori M, Salgado H. Activation of 5-HT receptors inhibits GABAergic transmission by pre-and post-synaptic mechanisms in layer II/III of the juvenile rat auditory cortex. Synapse 2015; 69:115-27. [DOI: 10.1002/syn.21794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 11/27/2014] [Indexed: 12/11/2022]
Affiliation(s)
- Francisco García-Oscos
- School of Behavioral and Brain Sciences, University of Texas at Dallas; Richardson Texas
- Department of Psychiatry; University of Texas, Southwestern Medical Center; Dallas Texas
| | - Oswaldo Torres-Ramírez
- Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”; Universidad Autónoma de Yucatán, Mérida; Yucatán México
| | - Lu Dinh
- School of Behavioral and Brain Sciences, University of Texas at Dallas; Richardson Texas
| | - Luis Galindo-Charles
- Department of Psychiatry; University of Texas, Southwestern Medical Center; Dallas Texas
| | - Elsy Arlene Pérez Padilla
- Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”; Universidad Autónoma de Yucatán, Mérida; Yucatán México
| | - Juan Carlos Pineda
- Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”; Universidad Autónoma de Yucatán, Mérida; Yucatán México
| | - Marco Atzori
- School of Behavioral and Brain Sciences, University of Texas at Dallas; Richardson Texas
- Facultad de Ciencias; Universidad Autónoma de San Luis Potosí; San Luis Potosí México
| | - Humberto Salgado
- School of Behavioral and Brain Sciences, University of Texas at Dallas; Richardson Texas
- Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”; Universidad Autónoma de Yucatán, Mérida; Yucatán México
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Nakamura Y, Darnieder LM, Deeb TZ, Moss SJ. Regulation of GABAARs by phosphorylation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 72:97-146. [PMID: 25600368 PMCID: PMC5337123 DOI: 10.1016/bs.apha.2014.11.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
γ-Aminobutyric acid type A receptors (GABAARs) are the principal mediators of fast synaptic inhibition in the brain as well as the low persistent extrasynaptic inhibition, both of which are fundamental to proper brain function. Thus unsurprisingly, deficits in GABAARs are implicated in a number of neurological disorders and diseases. The complexity of GABAAR regulation is determined not only by the heterogeneity of these receptors but also by its posttranslational modifications, the foremost, and best characterized of which is phosphorylation. This review will explore the details of this dynamic process, our understanding of which has barely scratched the surface. GABAARs are regulated by a number of kinases and phosphatases, and its phosphorylation plays an important role in governing its trafficking, expression, and interaction partners. Here, we summarize the progress in understanding the role phosphorylation plays in the regulation of GABAARs. This includes how phosphorylation can affect the allosteric modulation of GABAARs, as well as signaling pathways that affect GABAAR phosphorylation. Finally, we discuss the dysregulation of GABAAR phosphorylation and its implication in disease processes.
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27
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Rombo DM, Dias RB, Duarte ST, Ribeiro JA, Lamsa KP, Sebastião AM. Adenosine A1Receptor Suppresses Tonic GABAAReceptor Currents in Hippocampal Pyramidal Cells and in a Defined Subpopulation of Interneurons. Cereb Cortex 2014; 26:1081-95. [DOI: 10.1093/cercor/bhu288] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Petrini EM, Barberis A. Diffusion dynamics of synaptic molecules during inhibitory postsynaptic plasticity. Front Cell Neurosci 2014; 8:300. [PMID: 25294987 PMCID: PMC4171989 DOI: 10.3389/fncel.2014.00300] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 09/05/2014] [Indexed: 12/24/2022] Open
Abstract
The plasticity of inhibitory transmission is expected to play a key role in the modulation of neuronal excitability and network function. Over the last two decades, the investigation of the determinants of inhibitory synaptic plasticity has allowed distinguishing presynaptic and postsynaptic mechanisms. While there has been a remarkable progress in the characterization of presynaptically-expressed plasticity of inhibition, the postsynaptic mechanisms of inhibitory long-term synaptic plasticity only begin to be unraveled. At postsynaptic level, the expression of inhibitory synaptic plasticity involves the rearrangement of the postsynaptic molecular components of the GABAergic synapse, including GABAA receptors, scaffold proteins and structural molecules. This implies a dynamic modulation of receptor intracellular trafficking and receptor surface lateral diffusion, along with regulation of the availability and distribution of scaffold proteins. This Review will focus on the mechanisms of the multifaceted molecular reorganization of the inhibitory synapse during postsynaptic plasticity, with special emphasis on the key role of protein dynamics to ensure prompt and reliable activity-dependent adjustments of synaptic strength.
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Affiliation(s)
- Enrica Maria Petrini
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genoa, Italy
| | - Andrea Barberis
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genoa, Italy
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29
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Albert PR, Vahid-Ansari F, Luckhart C. Serotonin-prefrontal cortical circuitry in anxiety and depression phenotypes: pivotal role of pre- and post-synaptic 5-HT1A receptor expression. Front Behav Neurosci 2014; 8:199. [PMID: 24936175 PMCID: PMC4047678 DOI: 10.3389/fnbeh.2014.00199] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 05/16/2014] [Indexed: 01/03/2023] Open
Abstract
Decreased serotonergic activity has been implicated in anxiety and major depression, and antidepressants directly or indirectly increase the long-term activity of the serotonin system. A key component of serotonin circuitry is the 5-HT1A autoreceptor, which functions as the major somatodendritic autoreceptor to negatively regulate the "gain" of the serotonin system. In addition, 5-HT1A heteroreceptors are abundantly expressed post-synaptically in the prefrontal cortex (PFC), amygdala, and hippocampus to mediate serotonin actions on fear, anxiety, stress, and cognition. Importantly, in the PFC 5-HT1A heteroreceptors are expressed on at least two antagonist neuronal populations: excitatory pyramidal neurons and inhibitory interneurons. Rodent models implicate the 5-HT1A receptor in anxiety- and depression-like phenotypes with distinct roles for pre- and post-synaptic 5-HT1A receptors. In this review, we present a model of serotonin-PFC circuitry that integrates evidence from mouse genetic models of anxiety and depression involving knockout, suppression, over-expression, or mutation of genes of the serotonin system including 5-HT1A receptors. The model postulates that behavioral phenotype shifts as serotonin activity increases from none (depressed/aggressive not anxious) to low (anxious/depressed) to high (anxious, not depressed). We identify a set of conserved transcription factors including Deaf1, Freud-1/CC2D1A, Freud-2/CC2D1B and glucocorticoid receptors that may confer deleterious regional changes in 5-HT1A receptors in depression, and how future treatments could target these mechanisms. Further studies to specifically test the roles and regulation of pyramidal vs. interneuronal populations of 5-HT receptors are needed better understand the role of serotonin in anxiety and depression and to devise more effective targeted therapeutic approaches.
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Affiliation(s)
- Paul R Albert
- Neuroscience, Ottawa Hospital Research Institute, University of Ottawa Ottawa, ON, Canada
| | - Faranak Vahid-Ansari
- Neuroscience, Ottawa Hospital Research Institute, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa ON, Canada
| | - Christine Luckhart
- Neuroscience, Ottawa Hospital Research Institute, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa ON, Canada
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Deidda G, Bozarth IF, Cancedda L. Modulation of GABAergic transmission in development and neurodevelopmental disorders: investigating physiology and pathology to gain therapeutic perspectives. Front Cell Neurosci 2014; 8:119. [PMID: 24904277 PMCID: PMC4033255 DOI: 10.3389/fncel.2014.00119] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/14/2014] [Indexed: 01/30/2023] Open
Abstract
During mammalian ontogenesis, the neurotransmitter GABA is a fundamental regulator of neuronal networks. In neuronal development, GABAergic signaling regulates neural proliferation, migration, differentiation, and neuronal-network wiring. In the adult, GABA orchestrates the activity of different neuronal cell-types largely interconnected, by powerfully modulating synaptic activity. GABA exerts these functions by binding to chloride-permeable ionotropic GABAA receptors and metabotropic GABAB receptors. According to its functional importance during development, GABA is implicated in a number of neurodevelopmental disorders such as autism, Fragile X, Rett syndrome, Down syndrome, schizophrenia, Tourette's syndrome and neurofibromatosis. The strength and polarity of GABAergic transmission is continuously modulated during physiological, but also pathological conditions. For GABAergic transmission through GABAA receptors, strength regulation is achieved by different mechanisms such as modulation of GABAA receptors themselves, variation of intracellular chloride concentration, and alteration in GABA metabolism. In the never-ending effort to find possible treatments for GABA-related neurological diseases, of great importance would be modulating GABAergic transmission in a safe and possibly physiological way, without the dangers of either silencing network activity or causing epileptic seizures. In this review, we will discuss the different ways to modulate GABAergic transmission normally at work both during physiological and pathological conditions. Our aim is to highlight new research perspectives for therapeutic treatments that reinstate natural and physiological brain functions in neuro-pathological conditions.
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Affiliation(s)
- Gabriele Deidda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
| | - Ignacio F Bozarth
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
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Fritschy JM, Panzanelli P. GABAAreceptors and plasticity of inhibitory neurotransmission in the central nervous system. Eur J Neurosci 2014; 39:1845-65. [DOI: 10.1111/ejn.12534] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 01/29/2014] [Accepted: 01/29/2014] [Indexed: 12/11/2022]
Affiliation(s)
- Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology; University of Zurich; Winterthurerstrasse 190 8057 Zurich Switzerland
- Neuroscience Center Zurich; University of Zurich and ETH; Zurich Switzerland
| | - Patrizia Panzanelli
- Department of Neuroscience Rita Levi Montalcini; University of Turin; Turin Italy
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Bright DP, Smart TG. Methods for recording and measuring tonic GABAA receptor-mediated inhibition. Front Neural Circuits 2013; 7:193. [PMID: 24367296 PMCID: PMC3852068 DOI: 10.3389/fncir.2013.00193] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 11/18/2013] [Indexed: 01/12/2023] Open
Abstract
Tonic inhibitory conductances mediated by GABAA receptors have now been identified and characterized in many different brain regions. Most experimental studies of tonic GABAergic inhibition have been carried out using acute brain slice preparations but tonic currents have been recorded under a variety of different conditions. This diversity of recording conditions is likely to impact upon many of the factors responsible for controlling tonic inhibition and can make comparison between different studies difficult. In this review, we will firstly consider how various experimental conditions, including age of animal, recording temperature and solution composition, are likely to influence tonic GABAA conductances. We will then consider some technical considerations related to how the tonic conductance is measured and subsequently analyzed, including how the use of current noise may provide a complementary and reliable method for quantifying changes in tonic current.
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Affiliation(s)
- Damian P Bright
- Department of Neuroscience, Physiology and Pharmacology, University College London London, UK
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, University College London London, UK
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Connelly WM, Errington AC, Di Giovanni G, Crunelli V. Metabotropic regulation of extrasynaptic GABAA receptors. Front Neural Circuits 2013; 7:171. [PMID: 24298239 PMCID: PMC3829460 DOI: 10.3389/fncir.2013.00171] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 10/03/2013] [Indexed: 01/28/2023] Open
Abstract
A large body of work now shows the importance of GABAA receptor-mediated tonic inhibition in regulating CNS function. However, outside of pathological conditions, there is relatively little evidence that the magnitude of tonic inhibition is itself under regulation. Here we review the mechanisms by which tonic inhibition is known to be modulated, and outline the potential behavioral consequences of this modulation. Specifically, we address the ability of protein kinase A and C to phosphorylate the extrasynaptic receptors responsible for the tonic GABAA current, and how G-protein coupled receptors can regulate tonic inhibition through these effectors. We then speculate about the possible functional consequences of regulating the magnitude of the tonic GABAA current.
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Affiliation(s)
- William M Connelly
- Neuroscience Division, Cardiff School of Biosciences, Cardiff University Cardiff, UK
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