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NMDA Receptor Activation and Ca 2+/PKC Signaling in Nicotine-Induced GABA Transport Shift in Embryonic Chick Retina. Neurochem Res 2023; 48:2104-2115. [PMID: 36792758 DOI: 10.1007/s11064-023-03870-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/23/2022] [Accepted: 01/21/2023] [Indexed: 02/17/2023]
Abstract
Nicotinic receptors are present in the retina of different vertebrates, and in the chick retina, it is present during early development throughout to post-hatching. These receptors are activated by nicotine, an alkaloid with addictive and neurotransmitter release modulation properties, such as GABA signaling. Here we evaluated the mechanisms of nicotine signaling in the avian retina during the development of neuron-glia cells at a stage where synapses are peaking. Nicotine almost halved [3H]-GABA uptake, reducing it by 45% whilst increasing more than two-fold [3H]-GABA release in E12 embryonic chick retinas. Additionally, nicotine mediated a 33% increase in [3H]-D-aspartate release. MK-801 50 μM blocked 66% of nicotine-induced [3H]-GABA release and Gö 6983 100 nM prevented the nicotine-induced reduction in [3H]-GABA uptake by rescuing 40% of this neurotransmitter uptake, implicating NMDAR and PKC (respectively) in the nicotinic responses. In addition, NO-711 prevented [3H]-GABA uptake and release induced by nicotine. Furthermore, the relevance of calcium influx for PKC activation was evidenced through fura-2 imaging. We conclude that the shift of GABA transport mediated by nicotine promotes GABA release by inducing transporter reversal via nicotine-induced EAA release through EAATs, or by a direct effect of nicotine in activating nicotinic receptors permeable to calcium and promoting PKC pathway activation and shifting GAT-1 activity, both prompting calcium influx, and activation of the PKC pathway and shifting GAT-1 activity.
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2
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Joseph D, Nayak SR, Penmatsa A. Structural insights into GABA transport inhibition using an engineered neurotransmitter transporter. EMBO J 2022; 41:e110735. [PMID: 35796008 PMCID: PMC9340486 DOI: 10.15252/embj.2022110735] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/08/2022] [Accepted: 06/12/2022] [Indexed: 01/14/2023] Open
Abstract
γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter, and its levels in the synaptic space are controlled by the GABA transporter isoforms (GATs). GATs are structurally related to biogenic amine transporters but display interactions with distinct inhibitors used as anti-epileptics. In this study, we engineer the binding pocket of Drosophila melanogaster dopamine transporter to resemble GAT1 and determine high-resolution X-ray structures of the modified transporter in the substrate-free state and in complex with GAT1 inhibitors NO711 and SKF89976a that are analogs of tiagabine, a medication prescribed for the treatment of partial seizures. We observe that the primary binding site undergoes substantial shifts in subsite architecture in the modified transporter to accommodate the two GAT1 inhibitors. We also observe that SKF89976a additionally interacts at an allosteric site in the extracellular vestibule, yielding an occluded conformation. Interchanging SKF89976a interacting residue in the extracellular loop 4 between GAT1 and dDAT suggests a role for this motif in the selective control of neurotransmitter uptake. Our findings, therefore, provide vital insights into the organizational principles dictating GAT1 activity and inhibition.
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Affiliation(s)
- Deepthi Joseph
- Molecular Biophysics UnitIndian Institute of ScienceBangaloreIndia
| | | | - Aravind Penmatsa
- Molecular Biophysics UnitIndian Institute of ScienceBangaloreIndia
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3
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Activation of the α1β2γ2L GABA A Receptor by Physiological Agonists. Biomolecules 2021; 11:biom11121864. [PMID: 34944508 PMCID: PMC8699469 DOI: 10.3390/biom11121864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/02/2021] [Accepted: 12/09/2021] [Indexed: 11/21/2022] Open
Abstract
The Cl− permeable GABAA receptor is a major contributor to cellular inhibition in the brain. The receptor is normally activated by synaptically-released or ambient GABA but is sensitive to a number of physiological compounds such as β-alanine, taurine, and neurosteroids that, to various degrees, activate the receptor and modulate responses either to the transmitter or to each other. Here, we describe α1β2γ2L GABAA receptor activation and modulation by combinations of orthosteric and allosteric activators. The overall goal was to gain insight into how changes in the levels of endogenous agonists modulate receptor activity and influence cellular inhibition. Experimental observations and simulations are described in the framework of a cyclic concerted transition model. We also provide general analytical solutions for the analysis of electrophysiological data collected in the presence of combinations of active compounds.
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4
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Ryan RM, Ingram SL, Scimemi A. Regulation of Glutamate, GABA and Dopamine Transporter Uptake, Surface Mobility and Expression. Front Cell Neurosci 2021; 15:670346. [PMID: 33927596 PMCID: PMC8076567 DOI: 10.3389/fncel.2021.670346] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 03/15/2021] [Indexed: 01/31/2023] Open
Abstract
Neurotransmitter transporters limit spillover between synapses and maintain the extracellular neurotransmitter concentration at low yet physiologically meaningful levels. They also exert a key role in providing precursors for neurotransmitter biosynthesis. In many cases, neurons and astrocytes contain a large intracellular pool of transporters that can be redistributed and stabilized in the plasma membrane following activation of different signaling pathways. This means that the uptake capacity of the brain neuropil for different neurotransmitters can be dynamically regulated over the course of minutes, as an indirect consequence of changes in neuronal activity, blood flow, cell-to-cell interactions, etc. Here we discuss recent advances in the mechanisms that control the cell membrane trafficking and biophysical properties of transporters for the excitatory, inhibitory and modulatory neurotransmitters glutamate, GABA, and dopamine.
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Affiliation(s)
- Renae M. Ryan
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Susan L. Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, United States
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5
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Pierce SR, Germann AL, Evers AS, Steinbach JH, Akk G. Reduced Activation of the Synaptic-Type GABA A Receptor Following Prolonged Exposure to Low Concentrations of Agonists: Relationship between Tonic Activity and Desensitization. Mol Pharmacol 2020; 98:762-769. [PMID: 32978327 DOI: 10.1124/molpharm.120.000088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/09/2020] [Indexed: 01/16/2023] Open
Abstract
Synaptic GABAA receptors are alternately exposed to short pulses of a high, millimolar concentration of GABA and prolonged periods of low, micromolar concentration of the transmitter. Prior work has indicated that exposure to micromolar concentrations of GABA can both activate the postsynaptic receptors generating sustained low-amplitude current and desensitize the receptors, thereby reducing the peak amplitude of subsequent synaptic response. However, the precise relationship between tonic activation and reduction of peak response is not known. Here, we have measured the effect of prolonged exposure to GABA or the combination of GABA and the neurosteroid allopregnanolone, which was intended to desensitize a fraction of receptors, on a subsequent response to a high concentration of agonist in human α1β3γ2L receptors expressed in Xenopus oocytes. We show that the reduction in the peak amplitude of the post-exposure test response correlates with the open probability of the preceding desensitizing response. Curve fitting of the inhibitory relationship yielded an IC50 of 12.5 µM and a Hill coefficient of -1.61. The activation and desensitization data were mechanistically analyzed in the framework of a three-state Resting-Active-Desensitized model. Using the estimated affinity, efficacy, and desensitization parameters, we calculated the amount of desensitization that would accumulate during a long (2-minute) application of GABA or GABA plus allopregnanolone. The results indicate that accumulation of desensitization depends on the level of activity rather than agonist or potentiator concentration per se. We estimate that in the presence of 1 µM GABA, approximately 5% of α1β3γ2L receptors are functionally eliminated because of desensitization. SIGNIFICANCE STATEMENT: We present an analytical approach to quantify and predict the loss of activatable GABAA receptors due to desensitization in the presence of transmitter and the steroid allopregnanolone. The findings indicate that the peak amplitude of the synaptic response is influenced by ambient GABA and that changes in ambient concentrations of the transmitter and other GABAergic agents can modify tonically and phasically activated synaptic receptors in opposite directions.
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Affiliation(s)
- Spencer R Pierce
- Department of Anesthesiology (S.R.P., A.L.G., A.S.E., J.H.S., G.A.) and the Taylor Family Institute for Innovative Psychiatric Research (A.S.E., J.H.S., G.A.), Washington University School of Medicine, St. Louis, Missouri
| | - Allison L Germann
- Department of Anesthesiology (S.R.P., A.L.G., A.S.E., J.H.S., G.A.) and the Taylor Family Institute for Innovative Psychiatric Research (A.S.E., J.H.S., G.A.), Washington University School of Medicine, St. Louis, Missouri
| | - Alex S Evers
- Department of Anesthesiology (S.R.P., A.L.G., A.S.E., J.H.S., G.A.) and the Taylor Family Institute for Innovative Psychiatric Research (A.S.E., J.H.S., G.A.), Washington University School of Medicine, St. Louis, Missouri
| | - Joe Henry Steinbach
- Department of Anesthesiology (S.R.P., A.L.G., A.S.E., J.H.S., G.A.) and the Taylor Family Institute for Innovative Psychiatric Research (A.S.E., J.H.S., G.A.), Washington University School of Medicine, St. Louis, Missouri
| | - Gustav Akk
- Department of Anesthesiology (S.R.P., A.L.G., A.S.E., J.H.S., G.A.) and the Taylor Family Institute for Innovative Psychiatric Research (A.S.E., J.H.S., G.A.), Washington University School of Medicine, St. Louis, Missouri
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6
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Chazalon M, Paredes-Rodriguez E, Morin S, Martinez A, Cristóvão-Ferreira S, Vaz S, Sebastiao A, Panatier A, Boué-Grabot E, Miguelez C, Baufreton J. GAT-3 Dysfunction Generates Tonic Inhibition in External Globus Pallidus Neurons in Parkinsonian Rodents. Cell Rep 2019; 23:1678-1690. [PMID: 29742425 DOI: 10.1016/j.celrep.2018.04.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 03/08/2018] [Accepted: 04/02/2018] [Indexed: 12/26/2022] Open
Abstract
The external globus pallidus (GP) is a key GABAergic hub in the basal ganglia (BG) circuitry, a neuronal network involved in motor control. In Parkinson's disease (PD), the rate and pattern of activity of GP neurons are profoundly altered and contribute to the motor symptoms of the disease. In rodent models of PD, the striato-pallidal pathway is hyperactive, and extracellular GABA concentrations are abnormally elevated in the GP, supporting the hypothesis of an alteration of neuronal and/or glial clearance of GABA. Here, we discovered the existence of persistent GABAergic tonic inhibition in GP neurons of dopamine-depleted (DD) rodent models. We showed that glial GAT-3 transporters are downregulated while neuronal GAT-1 function remains normal in DD rodents. Finally, we showed that blocking GAT-3 activity in vivo alters the motor coordination of control rodents, suggesting that GABAergic tonic inhibition in the GP contributes to the pathophysiology of PD.
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Affiliation(s)
- Marine Chazalon
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | | | - Stéphanie Morin
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Audrey Martinez
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Sofia Cristóvão-Ferreira
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Sandra Vaz
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Ana Sebastiao
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, and Unit of Neuroscience, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Aude Panatier
- INSERM U1215, Neurocentre Magendie, 33000 Bordeaux, France; Université de Bordeaux, 33000 Bordeaux, France
| | - Eric Boué-Grabot
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France
| | - Cristina Miguelez
- Department of Pharmacology, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - Jérôme Baufreton
- Université de Bordeaux, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France; CNRS UMR 5293, Institut des Maladies Neurodégénératives, 33000 Bordeaux, France.
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7
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Manville RW, Papanikolaou M, Abbott GW. M-Channel Activation Contributes to the Anticonvulsant Action of the Ketone Body β-Hydroxybutyrate. J Pharmacol Exp Ther 2019; 372:148-156. [PMID: 31757819 DOI: 10.1124/jpet.119.263350] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 11/20/2019] [Indexed: 12/26/2022] Open
Abstract
Ketogenic diets are effective therapies for refractory epilepsy, yet the underlying mechanisms are incompletely understood. The anticonvulsant efficacy of ketogenic diets correlates positively to the serum concentration of β-hydroxybutyrate (BHB), the primary ketone body generated by ketosis. Voltage-gated potassium channels generated by KCNQ2-5 subunits, especially KCNQ2/3 heteromers, generate the M-current, a therapeutic target for synthetic anticonvulsants. Here, we report that BHB directly activates KCNQ2/3 channels (EC50 = 0.7 µM), via a highly conserved S5 tryptophan (W265) on KCNQ3. BHB was also acutely effective as an anticonvulsant in the pentylene tetrazole (PTZ) seizure assay in mice. Strikingly, coadministration of γ-amino-β-hydroxybutyric acid, a high-affinity KCNQ2/3 partial agonist that also acts via KCNQ3-W265, similarly reduced the efficacy of BHB in KCNQ2/3 channel activation in vitro and in the PTZ seizure assay in vivo. Our results uncover a novel, unexpected molecular basis for anticonvulsant effects of the major ketone body induced by ketosis. SIGNIFICANCE STATEMENT: Ketogenic diets are used to treat refractory epilepsy but the therapeutic mechanism is not fully understood. Here, we show that clinically relevant concentrations of β-hydroxybutyrate, the primary ketone body generated during ketogenesis, activates KCNQ2/3 potassium channels by binding to a specific site on KCNQ3, an effect known to reduce neuronal excitability. We provide evidence using a mouse chemoconvulsant model that KCNQ2/3 activation contributes to the antiepileptic action of β-hydroxybutyrate.
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Affiliation(s)
- Rían W Manville
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
| | - Maria Papanikolaou
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, California
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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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Blanco-Centurion C, Bendell E, Zou B, Sun Y, Shiromani PJ, Liu M. VGAT and VGLUT2 expression in MCH and orexin neurons in double transgenic reporter mice. IBRO Rep 2018; 4:44-49. [PMID: 30155524 PMCID: PMC6111069 DOI: 10.1016/j.ibror.2018.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 04/23/2018] [Accepted: 05/09/2018] [Indexed: 11/11/2022] Open
Abstract
MCH neurons contain neither VGAT nor VGLUT2. Majority of orexin neurons contain VGLUT2. MCH neurons do not contain orexin.
The neuropeptides orexin and melanin-concentrating hormone (MCH), as well as the neurotransmitters GABA (γ-Aminobutyric acid) and glutamate are chief modulators of the sleep-wake states in the posterior hypothalamus. To investigate co-expression of vesicular GABA transporter (VGAT, a marker of GABA neurons) and the vesicular glutamate transporter-2 (VGLUT2, a marker of glutamate neurons) in orexin and MCH neurons, we generated two transgenic mouse lines. One line selectively expressed the reporter gene EYFP in VGAT+ neurons, whereas the other line expressed reporter gene tdTomato in VGLUT2+ neurons. Co-localization between these genetic reporters and orexin or MCH immunofluorescent tags was determined using 3D computer reconstructions of Z stacks that were acquired using a multiphoton laser confocal microscope. Our results demonstrated that MCH neurons expressed neither VGAT nor VGLUT2, suggesting MCH neurons are a separate cluster of cells from VGAT+ GABAergic neurons and VGLUT2+ glutamatergic neurons. Moreover, most orexin neurons expressed VGLUT2, indicating these neurons are glutamatergic. Our data suggested that in the posterior hypothalamus there are four major distinct groups of neurons: VGAT+, orexin+/VGLUT2+, orexin-/VGLUT2+, and MCH neurons. This study facilitated our understanding of the role of these neurotransmitters and neuropeptides in relation to sleep/wake regulation.
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Key Words
- Arousal
- CeA, central nucleus of amygdala
- GABA
- GABA-γ, Aminobutyric acid
- GAD65, glutamic acid decarboxylase-65
- GAD67, glutamic acid decarboxylase-67
- Gad1, Glutamate decarboxylase 1
- Glutamate
- MCH, melanin concentrating hormone
- NREM, non-rapid eye movement
- REM, rapid eye movement
- RTN, reticular thalamic nucleus
- SSC, somatosensory cortex
- Sleep
- VGAT, vesicular GABA transporter
- VGLUT2, vesicular glutamate transporter-2
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Affiliation(s)
- Carlos Blanco-Centurion
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Emmaline Bendell
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Bingyu Zou
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Ying Sun
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Priyattam J Shiromani
- Ralph H. Johnson VA Medical Center, Charleston, SC, 29425, USA.,Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Meng Liu
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, 29425, USA
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10
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Direct neurotransmitter activation of voltage-gated potassium channels. Nat Commun 2018; 9:1847. [PMID: 29748663 PMCID: PMC5945843 DOI: 10.1038/s41467-018-04266-w] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 04/16/2018] [Indexed: 11/25/2022] Open
Abstract
Voltage-gated potassium channels KCNQ2–5 generate the M-current, which controls neuronal excitability. KCNQ2–5 subunits each harbor a high-affinity anticonvulsant drug-binding pocket containing an essential tryptophan (W265 in human KCNQ3) conserved for >500 million years, yet lacking a known physiological function. Here, phylogenetic analysis, electrostatic potential mapping, in silico docking, electrophysiology, and radioligand binding assays reveal that the anticonvulsant binding pocket evolved to accommodate endogenous neurotransmitters including γ-aminobutyric acid (GABA), which directly activates KCNQ5 and KCNQ3 via W265. GABA, and endogenous metabolites β-hydroxybutyric acid (BHB) and γ-amino-β-hydroxybutyric acid (GABOB), competitively and differentially shift the voltage dependence of KCNQ3 activation. Our results uncover a novel paradigm: direct neurotransmitter activation of voltage-gated ion channels, enabling chemosensing of the neurotransmitter/metabolite landscape to regulate channel activity and cellular excitability. M-current is conveyed by voltage-sensitive KCNQ channels, which are enriched in GABAergic neurons and are activated by anticonvulsants such as retigabine. Here the authors show that GABA directly activates KCNQ3, at the residue required for its anticonvulsant activity.
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11
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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12
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 899] [Impact Index Per Article: 149.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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13
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Ning S, Kang Q, Fan D, Liu J, Xue C, Zhang X, Ding C, Zhang J, Peng Q, Ji Z. Protein 4.1R is Involved in the Transport of 5-Aminolevulinic Acid by Interaction with GATs in MEF Cells. Photochem Photobiol 2017; 94:173-178. [DOI: 10.1111/php.12842] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 08/30/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Shuwei Ning
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Qiaozhen Kang
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Dandan Fan
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
| | - Jingjing Liu
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
| | - Chaoyue Xue
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Xiaolin Zhang
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Cong Ding
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Jianying Zhang
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
| | - Qian Peng
- Department of Pathology; The Norwegian Radium Hospital; Oslo University Hospital; University of Oslo; Montebello Oslo Norway
| | - Zhenyu Ji
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
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14
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Moldavan M, Cravetchi O, Williams M, Irwin RP, Aicher SA, Allen CN. Localization and expression of GABA transporters in the suprachiasmatic nucleus. Eur J Neurosci 2015; 42:3018-32. [PMID: 26390912 DOI: 10.1111/ejn.13083] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/12/2015] [Accepted: 09/17/2015] [Indexed: 01/25/2023]
Abstract
GABA is a principal neurotransmitter in the suprachiasmatic hypothalamic nucleus (SCN), the master circadian clock. Despite the importance of GABA and GABA uptake for functioning of the circadian pacemaker, the localization and expression of GABA transporters (GATs) in the SCN has not been investigated. The present studies used Western blot analysis, immunohistochemistry and electron microscopy to demonstrate the presence of GABA transporter 1 (GAT1) and GAT3 in the SCN. By using light microscopy, GAT1 and GAT3 were co-localized throughout the SCN, but were not expressed in the perikarya of arginine vasopressin- or vasoactive intestinal peptide-immunoreactive (-ir) neurons of adult rats, nor in the neuronal processes labelled with the neurofilament heavy chain. Using electron microscopy, GAT1- and GAT3-ir was found in glial processes surrounding unlabelled neuronal perikarya, axons, dendrites, and enveloped symmetric and asymmetric axo-dendritic synapses. Glial fibrillary acidic protein-ir astrocytes grown in cell culture were immunopositive for GAT1 and GAT3 and both GATs could be observed in the same glial cell. These data demonstrate that synapses in the SCN function as 'tripartite' synapses consisting of presynaptic axon terminals, postsynaptic membranes and astrocytes that contain GABA transporters. This model suggests that astrocytes expressing both GATs may regulate the extracellular GABA, and thereby modulate the activity of neuronal networks in the SCN.
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Affiliation(s)
- Michael Moldavan
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Olga Cravetchi
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Melissa Williams
- Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Robert P Irwin
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Sue A Aicher
- Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Charles N Allen
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
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Affiliation(s)
- Andrea Barberis
- Neuroscience and Brain Technologies, Post-synaptic Mechanisms of GABAergic Transmission, Fondazione Istituto Italiano di Tecnologia Genova, Italy
| | - Alberto Bacci
- Inserm U 1127, Centre National de la Recherche Scientifique UMR 7225, Sorbonne Universités UPMC Paris 06, UMR S 11 Paris, France ; Institut du Cerveau et de la Moelle Épinière Paris, France
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16
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Scimemi A. Structure, function, and plasticity of GABA transporters. Front Cell Neurosci 2014; 8:161. [PMID: 24987330 PMCID: PMC4060055 DOI: 10.3389/fncel.2014.00161] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 05/27/2014] [Indexed: 11/13/2022] Open
Abstract
GABA transporters belong to a large family of neurotransmitter:sodium symporters. They are widely expressed throughout the brain, with different levels of expression in different brain regions. GABA transporters are present in neurons and in astrocytes and their activity is crucial to regulate the extracellular concentration of GABA under basal conditions and during ongoing synaptic events. Numerous efforts have been devoted to determine the structural and functional properties of GABA transporters. There is also evidence that the expression of GABA transporters on the cell membrane and their lateral mobility can be modulated by different intracellular signaling cascades. The strength of individual synaptic contacts and the activity of entire neuronal networks may be finely tuned by altering the density, distribution and diffusion rate of GABA transporters within the cell membrane. These findings are intriguing because they suggest the existence of complex regulatory systems that control the plasticity of GABAergic transmission in the brain. Here we review the current knowledge on the structural and functional properties of GABA transporters and highlight the molecular mechanisms that alter the expression and mobility of GABA transporters at central synapses.
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