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Qneibi M, Bdir S, Bdair M, Aldwaik SA, Sandouka D, Heeh M, Idais TI. AMPA receptor neurotransmission and therapeutic applications: A comprehensive review of their multifaceted modulation. Eur J Med Chem 2024; 266:116151. [PMID: 38237342 DOI: 10.1016/j.ejmech.2024.116151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/02/2024] [Accepted: 01/11/2024] [Indexed: 02/05/2024]
Abstract
The neuropharmacological community has shown a strong interest in AMPA receptors as critical components of excitatory synaptic transmission during the last fifteen years. AMPA receptors, members of the ionotropic glutamate receptor family, allow rapid excitatory neurotransmission in the brain. AMPA receptors, which are permeable to sodium and potassium ions, manage the bulk of the brain's rapid synaptic communications. This study thoroughly examines the recent developments in AMPA receptor regulation, focusing on a shift from single chemical illustrations to a more extensive investigation of underlying processes. The complex interplay of these modulators in modifying the function and structure of AMPA receptors is the main focus, providing insight into their influence on the speed of excitatory neurotransmission. This research emphasizes the potential of AMPA receptor modulation as a therapy for various neurological disorders such as epilepsy and Alzheimer's disease. Analyzing these regulators' sophisticated molecular details enhances our comprehension of neuropharmacology, representing a significant advancement in using AMPA receptors for treating intricate neurological conditions.
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Affiliation(s)
- Mohammad Qneibi
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine.
| | - Sosana Bdir
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Mohammad Bdair
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Samia Ammar Aldwaik
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Dana Sandouka
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | | | - Tala Iyad Idais
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
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2
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Li C, Li Z, Xu S, Jiang S, Ye Z, Yu B, Gong S, Li J, Hu Q, Feng B, Wang M, Lu C. Exogenous AMPA downregulates gamma-frequency network oscillation in CA3 of rat hippocampal slices. Sci Rep 2023; 13:10548. [PMID: 37386056 PMCID: PMC10310770 DOI: 10.1038/s41598-023-36876-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 06/12/2023] [Indexed: 07/01/2023] Open
Abstract
Pharmacologically-induced persistent hippocampal γ oscillation in area CA3 requires activation of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs). However, we demonstrated that exogenous AMPA dose-dependently inhibited carbachol (CCH)-induced γ oscillation in the CA3 area of rat hippocampal slices, but the underlying mechanism is not clear. Application of AMPARs antagonist NBQX (1 μM) did not affect γ oscillation power (γ power), nor AMPA-mediated γ power reduction. At 3 μM, NBQX had no effect on γ power but largely blocked AMPA-mediated γ power reduction. Ca2+-permeable AMPA receptor (CP-AMPAR) antagonist IEM1460 or CaMKK inhibitor STO-609 but not CaMKIIα inhibitor KN93 enhanced γ power, indicating that activation of CP-AMPAR or CaMKK negatively modulated CCH-induced γ oscillation. Either CP-AMPAR antagonist or CaMKK inhibitor alone did not affected AMPA-mediated γ power reduction, but co-administration of IEM1460 and NBQX (1 μM) largely prevented AMPA-mediated downregulation of γ suggesting that CP-AMPARs and CI-AMPARs are involved in AMPA downregulation of γ oscillation. The recurrent excitation recorded at CA3 stratum pyramidale was significantly reduced by AMPA application. Our results indicate that AMPA downregulation of γ oscillation may be related to the reduced recurrent excitation within CA3 local neuronal network due to rapid CI-AMPAR and CP-AMPAR activation.
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Affiliation(s)
- Chengzhang Li
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Zhenrong Li
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Sihan Xu
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Sanwei Jiang
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Zhenli Ye
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Bin Yu
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Shixiang Gong
- School of Information Science and Engineering, Yanshan University, Qinhuangdao, China
| | - Junmei Li
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Qilin Hu
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Bingyan Feng
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Mengmeng Wang
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Chengbiao Lu
- Henan International Key Laboratory for Noninvasive Neuromodulation/Key Laboratory of Brain Research of Henan Province, Department of Physiology & Pathophysiology, School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China.
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3
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Kumar J, Popescu GK, Gantz SC. GluD receptors are functional ion channels. Biophys J 2023; 122:2383-2395. [PMID: 37177782 PMCID: PMC10323023 DOI: 10.1016/j.bpj.2023.05.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 05/15/2023] Open
Abstract
In this article, we review contemporary evidence that GluD receptors are functional ion channels whose depolarizing currents contribute to their biological functions, akin to all other members of the ionotropic glutamate receptor (iGluR) family.
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Affiliation(s)
- Janesh Kumar
- Laboratory of Membrane Protein Biology, Council of Scientific and Industrial Research (CSIR)-Centre for Cellular and Molecular Biology, Hyderabad, Telangana, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Gabriela K Popescu
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, SUNY, Buffalo, New York
| | - Stephanie C Gantz
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa; Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa.
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Copeland DS, Gugel A, Gantz SC. Potentiation of neuronal activity by tonic GluD1 current in brain slices. EMBO Rep 2023:e56801. [PMID: 37154294 DOI: 10.15252/embr.202356801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/19/2023] [Accepted: 04/24/2023] [Indexed: 05/10/2023] Open
Abstract
Ion channel function of native delta glutamate receptors (GluDR ) is incompletely understood. Previously, we and others have shown that activation of Gαq protein-coupled receptors (GqPCR) produces a slow inward current carried by GluD1R . GluD1R also carries a tonic cation current of unknown cause. Here, using voltage-clamp electrophysiological recordings from adult mouse brain slices containing the dorsal raphe nucleus, we find no role of ongoing G-protein-coupled receptor activity in generating or sustaining tonic GluD1R currents. Neither augmentation nor disruption of G protein activity affects tonic GluD1R currents, suggesting that ongoing G-protein-coupled receptor activity does not give rise to tonic GluD1R currents. Further, the tonic GluD1R current is unaffected by the addition of external glycine or D-serine, which influences GluD2R current at millimolar concentrations. Instead, GqPCR-stimulated and tonic GluD1R currents are regulated by physiological levels of external calcium. In current-clamp recordings, block of GluD1R channels hyperpolarizes the membrane by ~7 mV at subthreshold potentials, reducing excitability. Thus, GluD1R carries a G-protein-independent tonic current that contributes to subthreshold neuronal excitation in the dorsal raphe nucleus.
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Affiliation(s)
- Daniel S Copeland
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
| | - Aleigha Gugel
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
| | - Stephanie C Gantz
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA
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5
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Webster JF, Beerens S, Wozny C. Effects of early life stress and subsequent re-exposure to stress on neuronal activity in the lateral habenula. Neuropsychopharmacology 2022; 48:745-753. [PMID: 36371544 PMCID: PMC10066304 DOI: 10.1038/s41386-022-01493-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/16/2022] [Accepted: 10/25/2022] [Indexed: 11/15/2022]
Abstract
Early life stress can result in depression in humans and depressive-like behaviour in rodents. In various animal models of depression, the lateral habenula (LHb) has been shown to become hyperactive immediately after early life stress. However, whether these pathological changes persist into adulthood is less well understood. Hence, we utilised the maternal separation (MS) model of depression to study how early life stress alters LHb physiology and depressive behaviour in adult mice. We find that only a weak depressive phenotype persists into adulthood which surprisingly is underpinned by LHb hypoactivity in acute slices, accompanied by alterations in both excitatory and inhibitory signalling. However, while we find the LHb to be less active at rest, we report that the neurons reside in a sensitised state where they are more responsive to re-exposure to stress in adulthood in the form of acute restraint, thus priming them to respond to aversive events with an increase in neuronal activity mediated by changes in glutamatergic transmission. These findings thus suggest that in addition to LHb hyperactivity, hypoactivity likely also promotes an adverse phenotype. Re-exposure to stress results in the reappearance of LHb hyperactivity offering a possible mechanism to explain how depression relapses occur following previous depressive episodes.
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Affiliation(s)
- Jack F Webster
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, UK
| | - Sanne Beerens
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, UK
| | - Christian Wozny
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, G4 0RE, UK. .,MSH Medical School Hamburg, Medical University, Institute for Molecular Medicine, 20457, Hamburg, Germany.
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6
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Langlois LD, Selvaraj P, Simmons SC, Gouty S, Zhang Y, Nugent FS. Repetitive mild traumatic brain injury induces persistent alterations in spontaneous synaptic activity of hippocampal CA1 pyramidal neurons. IBRO Neurosci Rep 2022; 12:157-162. [PMID: 35746968 PMCID: PMC9210462 DOI: 10.1016/j.ibneur.2022.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/20/2021] [Accepted: 02/07/2022] [Indexed: 11/17/2022] Open
Abstract
Mild traumatic brain injury (mTBI) or concussion is the most common form of TBI which frequently results in persistent cognitive impairments and memory deficits in affected individuals [1]. Although most studies have investigated the role of hippocampal synaptic dysfunction in earlier time points following a single injury, the long-lasting effects of mTBI on hippocampal synaptic transmission following multiple brain concussions have not been well-elucidated. Using a repetitive closed head injury (3XCHI) mouse model of mTBI, we examined the alteration of spontaneous synaptic transmission onto hippocampal CA1 pyramidal neurons by recording spontaneous excitatory AMPA receptor (AMPAR)- and inhibitory GABAAR-mediated postsynaptic currents (sEPSCs and sIPSCs, respectively) in adult male mice 2-weeks following the injury. We found that mTBI potentiated postsynaptic excitatory AMPAR synaptic function while depressed postsynaptic inhibitory GABAAR synaptic function in CA1 pyramidal neurons. Additionally, mTBI slowed the decay time of AMPAR currents while shortened the decay time of GABAAR currents suggesting changes in AMPAR and GABAAR subunit composition by mTBI. On the other hand, mTBI reduced the frequency of sEPSCs while enhanced the frequency of sIPSCs resulting in a lower ratio of sEPSC/sIPSC frequency in CA1 pyramidal neurons of mTBI animals compared to sham animals. Altogether, our results suggest that mTBI induces persistent postsynaptic modifications in AMPAR and GABAAR function and their synaptic composition in CA1 neurons while triggering a compensatory shift in excitation/inhibition (E/I) balance of presynaptic drives towards more inhibitory synaptic drive to hippocampal CA1 cells. The persistent mTBI-induced CA1 synaptic dysfunction and E/I imbalance could contribute to deficits in hippocampal plasticity that underlies long-term hippocampal-dependent learning and memory deficits in mTBI patients long after the initial injury.
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Affiliation(s)
- Ludovic D. Langlois
- Uniformed Services University of the Health Sciences, Edward Hebert School of Medicine, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD 20814, USA
| | - Prabhuanand Selvaraj
- Uniformed Services University of the Health Sciences, Edward Hebert School of Medicine, Department of Anatomy, Physiology and Genetics, Bethesda, MD 20814, USA
| | - Sarah C. Simmons
- Uniformed Services University of the Health Sciences, Edward Hebert School of Medicine, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD 20814, USA
| | - Shawn Gouty
- Uniformed Services University of the Health Sciences, Edward Hebert School of Medicine, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD 20814, USA
| | - Yumin Zhang
- Uniformed Services University of the Health Sciences, Edward Hebert School of Medicine, Department of Anatomy, Physiology and Genetics, Bethesda, MD 20814, USA
- Corresponding authors.
| | - Fereshteh S. Nugent
- Uniformed Services University of the Health Sciences, Edward Hebert School of Medicine, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD 20814, USA
- Corresponding authors.
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Azarnia Tehran D, Kochlamazashvili G, Pampaloni NP, Sposini S, Shergill JK, Lehmann M, Pashkova N, Schmidt C, Löwe D, Napieczynska H, Heuser A, Plested AJR, Perrais D, Piper RC, Haucke V, Maritzen T. Selective endocytosis of Ca 2+-permeable AMPARs by the Alzheimer's disease risk factor CALM bidirectionally controls synaptic plasticity. SCIENCE ADVANCES 2022; 8:eabl5032. [PMID: 35613266 PMCID: PMC9132451 DOI: 10.1126/sciadv.abl5032] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 04/05/2022] [Indexed: 06/15/2023]
Abstract
AMPA-type glutamate receptors (AMPARs) mediate fast excitatory neurotransmission, and the plastic modulation of their surface levels determines synaptic strength. AMPARs of different subunit compositions fulfill distinct roles in synaptic long-term potentiation (LTP) and depression (LTD) to enable learning. Largely unknown endocytic mechanisms mediate the subunit-selective regulation of the surface levels of GluA1-homomeric Ca2+-permeable (CP) versus heteromeric Ca2+-impermeable (CI) AMPARs. Here, we report that the Alzheimer's disease risk factor CALM controls the surface levels of CP-AMPARs and thereby reciprocally regulates LTP and LTD in vivo to modulate learning. We show that CALM selectively facilitates the endocytosis of ubiquitinated CP-AMPARs via a mechanism that depends on ubiquitin recognition by its ANTH domain but is independent of clathrin. Our data identify CALM and related ANTH domain-containing proteins as the core endocytic machinery that determines the surface levels of CP-AMPARs to bidirectionally control synaptic plasticity and modulate learning in the mammalian brain.
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Affiliation(s)
- Domenico Azarnia Tehran
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Gaga Kochlamazashvili
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Niccolò P. Pampaloni
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, 10115 Berlin, Germany
| | - Silvia Sposini
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Jasmeet Kaur Shergill
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Department of Nanophysiology, Technische Universität Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Natalya Pashkova
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Claudia Schmidt
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Delia Löwe
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Hanna Napieczynska
- Animal Phenotyping, Max Delbrück Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Arnd Heuser
- Animal Phenotyping, Max Delbrück Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany
| | - Andrew J. R. Plested
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, 10115 Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Virchowweg 6, 10117 Berlin, Germany
| | - David Perrais
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Robert C. Piper
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Virchowweg 6, 10117 Berlin, Germany
- Freie Universität Berlin, Faculty of Biology, Chemistry and Pharmacy, 14195 Berlin, Germany
| | - Tanja Maritzen
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Department of Nanophysiology, Technische Universität Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
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Coombs ID, Cull-Candy SG. Single-channel mechanisms underlying the function, diversity and plasticity of AMPA receptors. Neuropharmacology 2021; 198:108781. [PMID: 34480912 DOI: 10.1016/j.neuropharm.2021.108781] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 08/18/2021] [Accepted: 08/31/2021] [Indexed: 12/29/2022]
Abstract
The functional properties of AMPA receptors shape many of the essential features of excitatory synaptic signalling in the brain, including high-fidelity point-to-point transmission and long-term plasticity. Understanding the behaviour and regulation of single AMPAR channels is fundamental in unravelling how central synapses carry, process and store information. There is now an abundance of data on the importance of alternative splicing, RNA editing, and phosphorylation of AMPAR subunits in determining central synaptic diversity. Furthermore, auxiliary subunits have emerged as pivotal players that regulate AMPAR channel properties and add further diversity. Single-channel studies have helped reveal a fascinating picture of the unique behaviour of AMPAR channels - their concentration-dependent single-channel conductance, the basis of their multiple-conductance states, and the influence of auxiliary proteins in controlling many of their gating and conductance properties. Here we summarize basic hallmarks of AMPAR single-channels, in relation to function, diversity and plasticity. We also present data that reveal an unexpected feature of AMPAR sublevel behaviour. This article is part of the special Issue on 'Glutamate Receptors - AMPA receptors'.
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Affiliation(s)
- Ian D Coombs
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Stuart G Cull-Candy
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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9
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Pampaloni NP, Plested AJR. Slow excitatory synaptic currents generated by AMPA receptors. J Physiol 2021; 600:217-232. [PMID: 34587649 DOI: 10.1113/jp280877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 09/01/2021] [Indexed: 12/28/2022] Open
Abstract
Decades of literature indicate that the AMPA-type glutamate receptor is among the fastest acting of all neurotransmitter receptors. These receptors are located at excitatory synapses, and conventional wisdom says that they activate in hundreds of microseconds, deactivate in milliseconds due to their low affinity for glutamate and also desensitize profoundly. These properties circumscribe AMPA receptor activation in both space and time. However, accumulating evidence shows that AMPA receptors can also activate with slow, indefatigable responses. They do so through interactions with auxiliary subunits that are able promote a switch to a high open probability, high-conductance 'superactive' mode. In this review, we show that any assumption that this phenomenon is limited to heterologous expression is false and rather that slow AMPA currents have been widely and repeatedly observed throughout the nervous system. Hallmarks of the superactive mode are a lack of desensitization, resistance to competitive antagonists and a current decay that outlives free glutamate by hundreds of milliseconds. Because the switch to the superactive mode is triggered by activation, AMPA receptors can generate accumulating 'pedestal' currents in response to repetitive stimulation, constituting a postsynaptic mechanism for short-term potentiation in the range 5-100 Hz. Further, slow AMPA currents span 'cognitive' time intervals in the 100 ms range (theta rhythms), of particular interest for hippocampal function, where slow AMPA currents are widely expressed in a synapse-specific manner. Here, we outline the implications that slow AMPA receptors have for excitatory synaptic transmission and computation in the nervous system.
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Affiliation(s)
- Niccolò P Pampaloni
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, Berlin, Germany.,Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, Berlin, Germany
| | - Andrew J R Plested
- Institute of Biology, Cellular Biophysics, Humboldt Universität zu Berlin, Berlin, Germany.,Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, Berlin, Germany
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