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Degro CE, Vida I, Booker SA. Postsynaptic GABA B-receptor mediated currents in diverse dentate gyrus interneuron types. Hippocampus 2024. [PMID: 39138952 DOI: 10.1002/hipo.23628] [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: 03/08/2024] [Revised: 06/24/2024] [Accepted: 07/19/2024] [Indexed: 08/15/2024]
Abstract
The processing of rich synaptic information in the dentate gyrus (DG) relies on a diverse population of inhibitory GABAergic interneurons to regulate cellular and circuit activity, in a layer-specific manner. Metabotropic GABAB-receptors (GABABRs) provide powerful inhibition to the DG circuit, on timescales consistent with behavior and learning, but their role in controlling the activity of interneurons is poorly understood with respect to identified cell types. We hypothesize that GABABRs display cell type-specific heterogeneity in signaling strength, which will have direct ramifications for signal processing in DG networks. To test this, we perform in vitro whole-cell patch-clamp recordings from identified DG principal cells and interneurons, followed by GABABR pharmacology, photolysis of caged GABA, and extracellular stimulation of endogenous GABA release to classify the cell type-specific inhibitory potential. Based on our previous classification of DG interneurons, we show that postsynaptic GABABR-mediated currents are present on all interneuron types albeit at different amplitudes, dependent largely on soma location and synaptic targets. GABABRs were coupled to inwardly-rectifying K+ channels that strongly reduced the excitability of those interneurons where large currents were observed. These data provide a systematic characterization of GABABR signaling in the rat DG to provide greater insight into circuit dynamics.
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Affiliation(s)
- Claudius E Degro
- Institute for Integrative Neuroanatomy, Charité-Universitätmedizin Berlin, Berlin, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité-Universitätmedizin Berlin, Berlin, Germany
| | - Sam A Booker
- Institute for Integrative Neuroanatomy, Charité-Universitätmedizin Berlin, Berlin, Germany
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
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2
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Martín-Belmonte A, Aguado C, Alfaro-Ruiz R, Kulik A, de la Ossa L, Moreno-Martínez AE, Alberquilla S, García-Carracedo L, Fernández M, Fajardo-Serrano A, Aso E, Shigemoto R, Martín ED, Fukazawa Y, Ciruela F, Luján R. Nanoarchitecture of Ca V2.1 channels and GABA B receptors in the mouse hippocampus: Impact of APP/PS1 pathology. Brain Pathol 2024:e13279. [PMID: 38887180 DOI: 10.1111/bpa.13279] [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: 02/06/2024] [Accepted: 05/27/2024] [Indexed: 06/20/2024] Open
Abstract
Voltage-gated CaV2.1 (P/Q-type) Ca2+ channels play a crucial role in regulating neurotransmitter release, thus contributing to synaptic plasticity and to processes such as learning and memory. Despite their recognized importance in neural function, there is limited information on their potential involvement in neurodegenerative conditions such as Alzheimer's disease (AD). Here, we aimed to explore the impact of AD pathology on the density and nanoscale compartmentalization of CaV2.1 channels in the hippocampus in association with GABAB receptors. Histoblotting experiments showed that the density of CaV2.1 channel was significantly reduced in the hippocampus of APP/PS1 mice in a laminar-dependent manner. CaV2.1 channel was enriched in the active zone of the axon terminals and was present at a very low density over the surface of dendritic tree of the CA1 pyramidal cells, as shown by quantitative SDS-digested freeze-fracture replica labelling (SDS-FRL). In APP/PS1 mice, the density of CaV2.1 channel in the active zone was significantly reduced in the strata radiatum and lacunosum-moleculare, while it remained unaltered in the stratum oriens. The decline in Cav2.1 channel density was found to be associated with a corresponding impairment in the GABAergic synaptic function, as evidenced by electrophysiological experiments carried out in the hippocampus of APP/PS1 mice. Remarkably, double SDS-FRL showed a co-clustering of CaV2.1 channel and GABAB1 receptor in nanodomains (~40-50 nm) in wild type mice, while in APP/PS1 mice this nanoarchitecture was absent. Together, these findings suggest that the AD pathology-induced reduction in CaV2.1 channel density and CaV2.1-GABAB1 de-clustering may play a role in the synaptic transmission alterations shown in the AD hippocampus. Therefore, uncovering these layer-dependent changes in P/Q calcium currents associated with AD pathology can benefit the development of future strategies for AD management.
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Affiliation(s)
- Alejandro Martín-Belmonte
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Carolina Aguado
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Rocío Alfaro-Ruiz
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Akos Kulik
- Institute for Physiology II, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Luis de la Ossa
- Departamento de Sistemas Informáticos, Escuela Superior de Ingeniería Informática, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Ana Esther Moreno-Martínez
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Samuel Alberquilla
- Laboratory of Neurophysiology and Synaptic Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Lucía García-Carracedo
- Laboratory of Neurophysiology and Synaptic Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Miriam Fernández
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Ana Fajardo-Serrano
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
| | - Ester Aso
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Eduardo D Martín
- Laboratory of Neurophysiology and Synaptic Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Yugo Fukazawa
- Division of Brain Structure and Function, Faculty of Medical Science, University of Fukui, Fukui, Japan
- Life Science Innovation Center, University of Fukui, Fukui, Japan
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Rafael Luján
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
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3
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Hannan SB, Penzinger R, Mickute G, Smart TG. CGP7930 - An allosteric modulator of GABA BRs, GABA ARs and inwardly-rectifying potassium channels. Neuropharmacology 2023; 238:109644. [PMID: 37422181 PMCID: PMC10951960 DOI: 10.1016/j.neuropharm.2023.109644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/01/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023]
Abstract
Type-A and -B GABA receptors (GABAARs/GABABRs) control brain function and behaviour by fine tuning neurotransmission. Over-time these receptors have become important therapeutic targets for treating neurodevelopmental and neuropsychiatric disorders. Several positive allosteric modulators (PAMs) of GABARs have reached the clinic and selective targeting of receptor subtypes is crucial. For GABABRs, CGP7930 is a widely used PAM for in vivo studies, but its full pharmacological profile has not yet been established. Here, we reveal that CGP7930 has multiple effects not only on GABABRs but also GABAARs, which for the latter involves potentiation of GABA currents, direct receptor activation, and also inhibition. Furthermore, at higher concentrations, CGP7930 also blocks G protein-coupled inwardly-rectifying K+ (GIRK) channels diminishing GABABR signalling in HEK 293 cells. In male and female rat hippocampal neuron cultures, CGP7930 allosteric effects on GABAARs caused prolonged rise and decay times and reduced the frequency of inhibitory postsynaptic currents and potentiated GABAAR-mediated tonic inhibition. Additional comparison between predominant synaptic- and extrasynaptic-isoforms of GABAAR indicated no evident subtype selectivity for CGP7930. In conclusion, our study of CGP7930 modulation of GABAARs, GABABRs and GIRK channels, indicates this compound is unsuitable for use as a specific GABABR PAM.
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Affiliation(s)
- Saad B Hannan
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Reka Penzinger
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Ginte Mickute
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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Hernandez-Martin E, Vidmark JSL, MacLean JA, Sanger TD. What is the effect of benzodiazepines on deep brain activity? A study in pediatric patients with dystonia. Front Neurol 2023; 14:1215572. [PMID: 37638186 PMCID: PMC10457157 DOI: 10.3389/fneur.2023.1215572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 08/01/2023] [Indexed: 08/29/2023] Open
Abstract
Introduction Benzodiazepines (BDZs) are commonly used to treat the symptoms of movement disorders; however, deep brain stimulation (DBS) has become a popular treatment for these disorders. Previous studies have investigated the effects of BDZ on cortical activity, no data are currently available on their effects on deep brain regions, nor on these regions' responses to DBS. How the BDZ affects the thalamus and basal ganglia in dystonia patients remains unknown. Methods DBS recordings were performed in ventral oralis anterior/posterior (VoaVop), ventral intermediate (VIM) and ventral anterior (VA) thalamic subnuclei, as well as globus pallidus interna (GPi) and subthalamic nucleus (STN). Evoked potentials (EP) and frequency domain analysis were performed to determine the BDZ effect on neural activities compared to the control condition (off-BDZ). Three male pediatric patients with dystonia treated with BDZ and undergoing depth electrode evaluation for clinical targeting were recruited for the study. Stimulation was administered at 25 and 55 Hz frequencies and recordings were simultaneously gathered through pairs of externalized stereoelectroencephalography (sEEG) electrodes. EP amplitude and the effect of stimulation on the frequency spectrum of activity were compared at baseline and following clinical administration of BDZ. Results Frequency analysis showed consistent reductions in activity during BDZ treatment in all studied brain regions for all patients. Evoked potential (EP) analysis showed increased subthalamic nucleus (STN) EP amplitude and decreased ventral intermediate (VIM) and STN EP amplitude during BDZ treatment. Interpretation BDZs reduce thalamic and basal ganglia activity in multiple regions and alter the efficacy of transmission between these regions. While the mechanism is unknown our results confirm the known widespread effects of this class of medications and identify specific areas within the motor system that are directly affected.
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Affiliation(s)
- Estefania Hernandez-Martin
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, United States
| | - Jessica S. L. Vidmark
- Department of Biomedical Engineering, University of California, Irvine, CA, United States
| | - Jennifer A. MacLean
- Department of Neurology, Children’s Health Orange County (CHOC), Orange, CA, United States
| | - Terence D. Sanger
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA, United States
- Department of Biomedical Engineering, University of California, Irvine, CA, United States
- Department of Neurology, Children’s Health Orange County (CHOC), Orange, CA, United States
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5
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Mansouri M, Kremser L, Nguyen TP, Kasugai Y, Caberlotto L, Gassmann M, Sarg B, Lindner H, Bettler B, Carboni L, Ferraguti F. Protein Networks Associated with Native Metabotropic Glutamate 1 Receptors (mGlu 1) in the Mouse Cerebellum. Cells 2023; 12:1325. [PMID: 37174725 PMCID: PMC10177021 DOI: 10.3390/cells12091325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/28/2023] [Accepted: 04/30/2023] [Indexed: 05/15/2023] Open
Abstract
The metabotropic glutamate receptor 1 (mGlu1) plays a pivotal role in synaptic transmission and neuronal plasticity. Despite the fact that several interacting proteins involved in the mGlu1 subcellular trafficking and intracellular transduction mechanisms have been identified, the protein network associated with this receptor in specific brain areas remains largely unknown. To identify novel mGlu1-associated protein complexes in the mouse cerebellum, we used an unbiased tissue-specific proteomic approach, namely co-immunoprecipitation followed by liquid chromatography/tandem mass spectrometry analysis. Many well-known protein complexes as well as novel interactors were identified, including G-proteins, Homer, δ2 glutamate receptor, 14-3-3 proteins, and Na/K-ATPases. A novel putative interactor, KCTD12, was further investigated. Reverse co-immunoprecipitation with anti-KCTD12 antibodies revealed mGlu1 in wild-type but not in KCTD12-knock-out homogenates. Freeze-fracture replica immunogold labeling co-localization experiments showed that KCTD12 and mGlu1 are present in the same nanodomain in Purkinje cell spines, although at a distance that suggests that this interaction is mediated through interposed proteins. Consistently, mGlu1 could not be co-immunoprecipitated with KCTD12 from a recombinant mammalian cell line co-expressing the two proteins. The possibility that this interaction was mediated via GABAB receptors was excluded by showing that mGlu1 and KCTD12 still co-immunoprecipitated from GABAB receptor knock-out tissue. In conclusion, this study identifies tissue-specific mGlu1-associated protein clusters including KCTD12 at Purkinje cell synapses.
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Affiliation(s)
- Mahnaz Mansouri
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.M.); (Y.K.)
| | - Leopold Kremser
- Institute of Medical Biochemistry, Protein Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria; (L.K.); (B.S.); (H.L.)
| | | | - Yu Kasugai
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.M.); (Y.K.)
| | - Laura Caberlotto
- Centre for Computational and Systems Biology (COSBI), The Microsoft Research University of Trento, 38068 Rovereto, Italy;
| | - Martin Gassmann
- Department of Biomedicine, Pharmazentrum, University of Basel, 4056 Basel, Switzerland; (M.G.); (B.B.)
| | - Bettina Sarg
- Institute of Medical Biochemistry, Protein Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria; (L.K.); (B.S.); (H.L.)
| | - Herbert Lindner
- Institute of Medical Biochemistry, Protein Core Facility, Medical University of Innsbruck, 6020 Innsbruck, Austria; (L.K.); (B.S.); (H.L.)
| | - Bernhard Bettler
- Department of Biomedicine, Pharmazentrum, University of Basel, 4056 Basel, Switzerland; (M.G.); (B.B.)
| | - Lucia Carboni
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, 40126 Bologna, Italy;
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria; (M.M.); (Y.K.)
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6
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Rollenhagen A, Anstötz M, Zimmermann K, Kasugai Y, Sätzler K, Molnar E, Ferraguti F, Lübke JHR. Layer-specific distribution and expression pattern of AMPA- and NMDA-type glutamate receptors in the barrel field of the adult rat somatosensory cortex: a quantitative electron microscopic analysis. Cereb Cortex 2023; 33:2342-2360. [PMID: 35732315 PMCID: PMC9977369 DOI: 10.1093/cercor/bhac212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/14/2022] Open
Abstract
AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and NMDA (N-methyl-d-aspartate) glutamate receptors are driving forces for synaptic transmission and plasticity at neocortical synapses. However, their distribution pattern in the adult rat neocortex is largely unknown and was quantified using freeze fracture replication combined with postimmunogold-labeling. Both receptors were co-localized at layer (L)4 and L5 postsynaptic densities (PSDs). At L4 dendritic shaft and spine PSDs, the number of gold grains detecting AMPA was similar, whereas at L5 shaft PSDs AMPA-receptors outnumbered those on spine PSDs. Their number was significantly higher at L5 vs. L4 PSDs. At L4 and L5 dendritic shaft PSDs, the number of gold grains detecting GluN1 was ~2-fold higher than at spine PSDs. The number of gold grains detecting the GluN1-subunit was higher for both shaft and spine PSDs in L5 vs. L4. Both receptors showed a large variability in L4 and L5. A high correlation between the number of gold grains and PSD size for both receptors and targets was observed. Both receptors were distributed over the entire PSD but showed a layer- and target-specific distribution pattern. The layer- and target-specific distribution of AMPA and GluN1 glutamate receptors partially contribute to the observed functional differences in synaptic transmission and plasticity in the neocortex.
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Affiliation(s)
- Astrid Rollenhagen
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo Brandt Str., Jülich 52425, Germany
| | - Max Anstötz
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo Brandt Str., Jülich 52425, Germany.,Institute of Anatomy II, Medical Faculty, University Hospital Düsseldorf, Heinrich-Heine-University, Universitätsstr. 1, Düsseldorf 40001, Germany
| | - Kerstin Zimmermann
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo Brandt Str., Jülich 52425, Germany
| | - Yu Kasugai
- Department of Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1a, Innsbruck A-6020, Austria
| | - Kurt Sätzler
- School of Biomedical Sciences, University of Ulster, Cromore Rd., Londonderry BT52 1SA, United Kingdom
| | - Elek Molnar
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1a, Innsbruck A-6020, Austria
| | - Joachim H R Lübke
- Institute of Neuroscience and Medicine INM-10, Research Centre Jülich GmbH, Leo Brandt Str., Jülich 52425, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH/Medical University Aachen, Pauwelstr. 30, Aachen 52074, Germany.,JARA Translational Medicine Jülich/Aachen, Germany
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Masoli S, Rizza MF, Tognolina M, Prestori F, D’Angelo E. Computational models of neurotransmission at cerebellar synapses unveil the impact on network computation. Front Comput Neurosci 2022; 16:1006989. [PMID: 36387305 PMCID: PMC9649760 DOI: 10.3389/fncom.2022.1006989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022] Open
Abstract
The neuroscientific field benefits from the conjoint evolution of experimental and computational techniques, allowing for the reconstruction and simulation of complex models of neurons and synapses. Chemical synapses are characterized by presynaptic vesicle cycling, neurotransmitter diffusion, and postsynaptic receptor activation, which eventually lead to postsynaptic currents and subsequent membrane potential changes. These mechanisms have been accurately modeled for different synapses and receptor types (AMPA, NMDA, and GABA) of the cerebellar cortical network, allowing simulation of their impact on computation. Of special relevance is short-term synaptic plasticity, which generates spatiotemporal filtering in local microcircuits and controls burst transmission and information flow through the network. Here, we present how data-driven computational models recapitulate the properties of neurotransmission at cerebellar synapses. The simulation of microcircuit models is starting to reveal how diverse synaptic mechanisms shape the spatiotemporal profiles of circuit activity and computation.
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Affiliation(s)
- Stefano Masoli
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | | | | | - Francesca Prestori
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- *Correspondence: Francesca Prestori,
| | - Egidio D’Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- IRCCS Mondino Foundation, Brain Connectivity Center, Pavia, Italy
- Egidio D’Angelo,
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8
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Ranjbar H, Soti M, Razavinasab M, Kohlmeier KA, Shabani M. The neglected role of endocannabinoid actions at TRPC channels in ataxia. Neurosci Biobehav Rev 2022; 141:104860. [PMID: 36087758 DOI: 10.1016/j.neubiorev.2022.104860] [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: 06/25/2022] [Revised: 08/24/2022] [Accepted: 09/03/2022] [Indexed: 12/01/2022]
Abstract
Transient receptor potential (TRP) channels are highly expressed in cells of the cerebellum including in the dendrites and somas of Purkinje cells (PCs). Their endogenous activation promotes influx of Ca2+ and Na+, resulting in depolarization. TRP channels can be activated by endogenous endocannabinoids (eCBs) and activity of TRP channels has been shown to modulate GABA and glutamate transmission. Ataxia is caused by disruption of multiple intracellular pathways which often involve changes in Ca2+ homeostasis that can result in neural cellular dysfunction and cell death. Based on available literature, alteration of transmission of eCBs would be expected to change activity of cerebellar TRP channels. Antagonists of the endocannabinoid system (ECS) including enzymes which break eCBs down have been shown to result in reductions in postsynaptic excitatory activity mediated by TRPC channels. Further, TRPC channel antagonists could modulate both pre and postsynaptically-mediated glutamatergic and GABAergic transmission, resulting in reductions in cell death due to excitotoxicity and dysfunctions caused by abnormal inhibitory signaling. Accordingly, TRP channels, and in particular the TRPC channel, represent a potential therapeutic target for management of ataxia.
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Affiliation(s)
- Hoda Ranjbar
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Monavareh Soti
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Moazamehosadat Razavinasab
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Kristi A Kohlmeier
- Department of Drug Design and Pharmacology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mohammad Shabani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
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9
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Salvati KA, Ritger ML, Davoudian PA, O’Dell F, Wyskiel DR, Souza GMPR, Lu AC, Perez-Reyes E, Drake JC, Yan Z, Beenhakker MP. OUP accepted manuscript. Brain 2022; 145:2332-2346. [PMID: 35134125 PMCID: PMC9337815 DOI: 10.1093/brain/awac037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 12/20/2021] [Accepted: 12/26/2021] [Indexed: 11/21/2022] Open
Abstract
Metabolism regulates neuronal activity and modulates the occurrence of epileptic seizures. Here, using two rodent models of absence epilepsy, we show that hypoglycaemia increases the occurrence of spike-wave seizures. We then show that selectively disrupting glycolysis in the thalamus, a structure implicated in absence epilepsy, is sufficient to increase spike-wave seizures. We propose that activation of thalamic AMP-activated protein kinase, a sensor of cellular energetic stress and potentiator of metabotropic GABAB-receptor function, is a significant driver of hypoglycaemia-induced spike-wave seizures. We show that AMP-activated protein kinase augments postsynaptic GABAB-receptor-mediated currents in thalamocortical neurons and strengthens epileptiform network activity evoked in thalamic brain slices. Selective thalamic AMP-activated protein kinase activation also increases spike-wave seizures. Finally, systemic administration of metformin, an AMP-activated protein kinase agonist and common diabetes treatment, profoundly increased spike-wave seizures. These results advance the decades-old observation that glucose metabolism regulates thalamocortical circuit excitability by demonstrating that AMP-activated protein kinase and GABAB-receptor cooperativity is sufficient to provoke spike-wave seizures.
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Affiliation(s)
- Kathryn A Salvati
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Epilepsy Research Laboratory and Weil Institute for Neurosciences, Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Matthew L Ritger
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Pasha A Davoudian
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- MD-PhD Program, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Finnegan O’Dell
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Daniel R Wyskiel
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Adam C Lu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joshua C Drake
- Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- The Robert M. Berne Center for Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Zhen Yan
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- The Robert M. Berne Center for Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mark P Beenhakker
- Correspondence to: Mark P. Beenhakker Department of Pharmacology University of Virginia School of Medicine Charlottesville, VA, 22908, USA E-mail:
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10
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Abstract
A substantial fraction of the human population suffers from chronic pain states, which often cannot be sufficiently treated with existing drugs. This calls for alternative targets and strategies for the development of novel analgesics. There is substantial evidence that the G protein-coupled GABAB receptor is involved in the processing of pain signals and thus has long been considered a valuable target for the generation of analgesics to treat chronic pain. In this review, the contribution of GABAB receptors to the generation and modulation of pain signals, their involvement in chronic pain states as well as their target suitability for the development of novel analgesics is discussed.
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Affiliation(s)
- Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
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11
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Roldán-Sastre A, Aguado C, Martín-Belmonte A, Alfaro-Ruiz R, Moreno-Martínez AE, Luján R. Cellular Diversity and Differential Subcellular Localization of the G-Protein G αo Subunit in the Mouse Cerebellum. Front Neuroanat 2021; 15:686279. [PMID: 34248508 PMCID: PMC8267243 DOI: 10.3389/fnana.2021.686279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/02/2021] [Indexed: 11/27/2022] Open
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) transduce signals from G protein-coupled receptors (GPCRs) to effector ion channels and enzymes Gαo, a member of the pertussis toxin-sensitive Gi/o family, is widely expressed in the brain, although its role within a neuronal context remains largely unknown. Using immunohistochemical and quantitative immunoelectron microscopy techniques, we have investigated the expression, cellular and subcellular localization of Gαo in the cerebellar cortex. Histoblot revealed that Gαo is expressed in many brain regions, including the cerebellum. At the cellular level, Gαo protein was distributed in Purkinje cells, basket cells, stellate cells, granule cells and Golgi cells. At the subcellular level, pre-embedding immunoelectron microscopy revealed mainly a postsynaptic localization of Gαo along the extrasynaptic plasma membrane of Purkinje cell dendritic shafts and spines, and dendrites of basket, stellate and granule cells. To a lesser extent, immunolabeling for Gαo was localized in different types of axon terminals establishing excitatory synapses. Moreover, post-embedding immunoelectron microscopy revealed the synaptic localization of Gαo on PSDs of glutamatergic synapses between Purkinje cell spines and parallel fiber terminals and its co-localization with GABAB1 in the same spines. Quantitative analysis of Gαo immunoparticles revealed they preferentially localized on the cytoplasmic face of the plasma membrane. Furthermore, the analysis revealed a high concentration of Gαo around excitatory synapses on Purkinje cell dendritic spines, but a uniform distribution in granule cell dendrites. These molecular-anatomical findings suggest that Gαo is a major signal transducer of specific GPCRs in different neuronal populations in the cerebellum.
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Affiliation(s)
- Alberto Roldán-Sastre
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department of Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Carolina Aguado
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department of Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Alejandro Martín-Belmonte
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department of Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Rocío Alfaro-Ruiz
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department of Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Ana Esther Moreno-Martínez
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department of Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Rafael Luján
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department of Ciencias Médicas, Facultad de Medicina, Universidad de Castilla-La Mancha, Albacete, Spain
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12
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mGluR1 signaling in cerebellar Purkinje cells: Subcellular organization and involvement in cerebellar function and disease. Neuropharmacology 2021; 194:108629. [PMID: 34089728 DOI: 10.1016/j.neuropharm.2021.108629] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 11/20/2022]
Abstract
The cerebellum is essential for the control, coordination, and learning of movements, and for certain aspects of cognitive function. Purkinje cells are the sole output neurons in the cerebellar cortex and therefore play crucial roles in the diverse functions of the cerebellum. The type 1 metabotropic glutamate receptor (mGluR1) is prominently enriched in Purkinje cells and triggers downstream signaling pathways that are required for functional and structural plasticity, and for synaptic responses. To understand how mGluR1 contributes to cerebellar functions, it is important to consider not only the operational properties of this receptor, but also its spatial organization and the molecular interactions that enable its proper functioning. In this review, we highlight how mGluR1 and its related signaling molecules are organized into tightly coupled microdomains to fulfill physiological functions. We also describe emerging evidence that altered mGluR1 signaling in Purkinje cells underlies cerebellar dysfunction in ataxias of human patients and mouse models.
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13
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Bhandari P, Vandael D, Fernández-Fernández D, Fritzius T, Kleindienst D, Önal C, Montanaro J, Gassmann M, Jonas P, Kulik A, Bettler B, Shigemoto R, Koppensteiner P. GABA B receptor auxiliary subunits modulate Cav2.3-mediated release from medial habenula terminals. eLife 2021; 10:68274. [PMID: 33913808 PMCID: PMC8121548 DOI: 10.7554/elife.68274] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/28/2021] [Indexed: 12/20/2022] Open
Abstract
The synaptic connection from medial habenula (MHb) to interpeduncular nucleus (IPN) is critical for emotion-related behaviors and uniquely expresses R-type Ca2+ channels (Cav2.3) and auxiliary GABAB receptor (GBR) subunits, the K+-channel tetramerization domain-containing proteins (KCTDs). Activation of GBRs facilitates or inhibits transmitter release from MHb terminals depending on the IPN subnucleus, but the role of KCTDs is unknown. We therefore examined the localization and function of Cav2.3, GBRs, and KCTDs in this pathway in mice. We show in heterologous cells that KCTD8 and KCTD12b directly bind to Cav2.3 and that KCTD8 potentiates Cav2.3 currents in the absence of GBRs. In the rostral IPN, KCTD8, KCTD12b, and Cav2.3 co-localize at the presynaptic active zone. Genetic deletion indicated a bidirectional modulation of Cav2.3-mediated release by these KCTDs with a compensatory increase of KCTD8 in the active zone in KCTD12b-deficient mice. The interaction of Cav2.3 with KCTDs therefore scales synaptic strength independent of GBR activation.
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Affiliation(s)
- Pradeep Bhandari
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - David Vandael
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | | | | | - David Kleindienst
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Cihan Önal
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Jacqueline Montanaro
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Martin Gassmann
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Peter Jonas
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Akos Kulik
- Institute of Physiology II, Faculty of Medicine, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Peter Koppensteiner
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
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14
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Abstract
Patients with essential tremor, vocal tremor, torticollis, myoclonus-dystonia and posthypoxic myoclonus often benefit in a surprisingly rapid and robust manner from ingestion of a modest amount of alcohol (ethanol). Despite considerable investigation, the mechanism of ethanol’s ability to produce this effect remains a mystery. In this paper, we review the pharmacology of ethanol and its analogue GHB (or sodium oxybate), summarize the published literature of alcohol-responsive hyperkinetic movement disorders, and demonstrate videos of patients we have treated over the last fifteen years with either an ethanol challenge or with chronic sodium oxybate therapy. We then propose a novel explanation for this phenomenon—namely, that ingestion of modest doses of ethanol (or sodium oxybate) normalizes the aberrant motor networks underling these disorders. We propose that alcohol and its analogues improve clinical symptoms and their physiologic correlate by restoring the normal firing pattern of the major outflow pathways of the cerebellum (the Purkinje cells and deep cerebellar nuclei), We present evidence to support this hypothesis in animal models and in affected patients, and suggest future investigations to test this model.
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15
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Lu AC, Lee CK, Kleiman-Weiner M, Truong B, Wang M, Huguenard JR, Beenhakker MP. Nonlinearities between inhibition and T-type calcium channel activity bidirectionally regulate thalamic oscillations. eLife 2020; 9:e59548. [PMID: 32902384 PMCID: PMC7529462 DOI: 10.7554/elife.59548] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/08/2020] [Indexed: 12/11/2022] Open
Abstract
Absence seizures result from 3 to 5 Hz generalized thalamocortical oscillations that depend on highly regulated inhibitory neurotransmission in the thalamus. Efficient reuptake of the inhibitory neurotransmitter GABA is essential, and reuptake failure worsens human seizures. Here, we show that blocking GABA transporters (GATs) in acute rat brain slices containing key parts of the thalamocortical seizure network modulates epileptiform activity. As expected, we found that blocking either GAT1 or GAT3 prolonged oscillations. However, blocking both GATs unexpectedly suppressed oscillations. Integrating experimental observations into single-neuron and network-level computational models shows how a non-linear dependence of T-type calcium channel gating on GABAB receptor activity regulates network oscillations. Receptor activity that is either too brief or too protracted fails to sufficiently open T-type channels necessary for sustaining oscillations. Only within a narrow range does prolonging GABAB receptor activity promote channel opening and intensify oscillations. These results have implications for therapeutics that modulate inhibition kinetics.
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Affiliation(s)
- Adam C Lu
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | | | | | - Brian Truong
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Megan Wang
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - John R Huguenard
- Department of Neurology, Stanford UniversityPalo AltoUnited States
| | - Mark P Beenhakker
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
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16
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Density of GABA B Receptors Is Reduced in Granule Cells of the Hippocampus in a Mouse Model of Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21072459. [PMID: 32252271 PMCID: PMC7177735 DOI: 10.3390/ijms21072459] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 12/22/2022] Open
Abstract
Metabotropic γ-aminobutyric acid (GABAB) receptors contribute to the control of network activity and information processing in hippocampal circuits by regulating neuronal excitability and synaptic transmission. The dysfunction in the dentate gyrus (DG) has been implicated in Alzheimer´s disease (AD). Given the involvement of GABAB receptors in AD, to determine their subcellular localisation and possible alteration in granule cells of the DG in a mouse model of AD at 12 months of age, we used high-resolution immunoelectron microscopic analysis. Immunohistochemistry at the light microscopic level showed that the regional and cellular expression pattern of GABAB1 was similar in an AD model mouse expressing mutated human amyloid precursor protein and presenilin1 (APP/PS1) and in age-matched wild type mice. High-resolution immunoelectron microscopy revealed a distance-dependent gradient of immunolabelling for GABAB receptors, increasing from proximal to distal dendrites in both wild type and APP/PS1 mice. However, the overall density of GABAB receptors at the neuronal surface of these postsynaptic compartments of granule cells was significantly reduced in APP/PS1 mice. Parallel to this reduction in surface receptors, we found a significant increase in GABAB1 at cytoplasmic sites. GABAB receptors were also detected at presynaptic sites in the molecular layer of the DG. We also found a decrease in plasma membrane GABAB receptors in axon terminals contacting dendritic spines of granule cells, which was more pronounced in the outer than in the inner molecular layer. Altogether, our data showing post- and presynaptic reduction in surface GABAB receptors in the DG suggest the alteration of the GABAB-mediated modulation of excitability and synaptic transmission in granule cells, which may contribute to the cognitive dysfunctions in the APP/PS1 model of AD.
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17
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Sakairi H, Kamikubo Y, Abe M, Ikeda K, Ichiki A, Tabata T, Kano M, Sakurai T. G Protein-Coupled Glutamate and GABA Receptors Form Complexes and Mutually Modulate Their Signals. ACS Chem Neurosci 2020; 11:567-578. [PMID: 31977183 DOI: 10.1021/acschemneuro.9b00599] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Molecular networks containing various proteins mediate many types of cellular processes. Elucidation of how the proteins interact will improve our understanding of the molecular integration and physiological and pharmacological propensities of the network. One of the most complicated and unexplained interactions between proteins is the inter-G protein-coupled receptor (GPCR) interaction. Recently, many studies have suggested that an interaction between neurotransmitter GPCRs may mediate diverse modalities of neural responses. The B-type gamma-aminobutyric acid (GABA) receptor (GBR) and type-1 metabotropic glutamate receptor (mGluR1) are GPCRs for GABA and glutamate, respectively, and each plays distinct roles in controlling neurotransmission. We have previously reported the possibility of their functional interaction in central neurons. Here, we examined the interaction of these GPCRs using stable cell lines and rat cerebella. Cell-surface imaging and coimmunoprecipitation analysis revealed that these GPCRs interact on the cell surface. Furthermore, fluorometry revealed that these GPCRs mutually modulate signal transduction. These findings provide solid evidence that mGluR1 and GBR have intrinsic abilities to form complexes and to mutually modulate signaling. These findings indicate that synaptic plasticity relies on a network of proteins far more complex than previously assumed.
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Affiliation(s)
- Hakushun Sakairi
- Department of Pharmacology, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Yuji Kamikubo
- Department of Pharmacology, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Masayoshi Abe
- Laboratory for Biological Information Processing, Faculty of Engineering and Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Keisuke Ikeda
- Laboratory for Biological Information Processing, Faculty of Engineering and Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Arata Ichiki
- Laboratory for Biological Information Processing, Faculty of Engineering and Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Toshihide Tabata
- Laboratory for Biological Information Processing, Faculty of Engineering and Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421, Japan
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18
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Booker SA, Harada H, Elgueta C, Bank J, Bartos M, Kulik A, Vida I. Presynaptic GABA B receptors functionally uncouple somatostatin interneurons from the active hippocampal network. eLife 2020; 9:51156. [PMID: 32073397 PMCID: PMC7060044 DOI: 10.7554/elife.51156] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 02/18/2020] [Indexed: 01/04/2023] Open
Abstract
Information processing in cortical neuronal networks relies on properly balanced excitatory and inhibitory neurotransmission. A ubiquitous motif for maintaining this balance is the somatostatin interneuron (SOM-IN) feedback microcircuit. Here, we investigated the modulation of this microcircuit by presynaptic GABAB receptors (GABABRs) in the rodent hippocampus. Whole-cell recordings from SOM-INs revealed that both excitatory and inhibitory synaptic inputs are strongly inhibited by GABABRs, while optogenetic activation of the interneurons shows that their inhibitory output is also strongly suppressed. Electron microscopic analysis of immunogold-labelled freeze-fracture replicas confirms that GABABRs are highly expressed presynaptically at both input and output synapses of SOM-INs. Activation of GABABRs selectively suppresses the recruitment of SOM-INs during gamma oscillations induced in vitro. Thus, axonal GABABRs are positioned to efficiently control the input and output synapses of SOM-INs and can functionally uncouple them from local network with implications for rhythmogenesis and the balance of entorhinal versus intrahippocampal afferents.
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Affiliation(s)
- Sam A Booker
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Harumi Harada
- Institute for Physiology II, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Claudio Elgueta
- Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Julia Bank
- Institute for Physiology II, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Akos Kulik
- Institute for Physiology II, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
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19
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Martín-Belmonte A, Aguado C, Alfaro-Ruíz R, Moreno-Martínez AE, de la Ossa L, Martínez-Hernández J, Buisson A, Früh S, Bettler B, Shigemoto R, Fukazawa Y, Luján R. Reduction in the neuronal surface of post and presynaptic GABA B receptors in the hippocampus in a mouse model of Alzheimer's disease. Brain Pathol 2019; 30:554-575. [PMID: 31729777 PMCID: PMC7317930 DOI: 10.1111/bpa.12802] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/04/2019] [Indexed: 12/25/2022] Open
Abstract
The hippocampus plays key roles in learning and memory and is a main target of Alzheimer's disease (AD), which causes progressive memory impairments. Despite numerous investigations about the processes required for the normal hippocampal functions, the neurotransmitter receptors involved in the synaptic deficits by which AD disables the hippocampus are not yet characterized. By combining histoblots, western blots, immunohistochemistry and high-resolution immunoelectron microscopic methods for GABAB receptors, this study provides a quantitative description of the expression and the subcellular localization of GABAB1 in the hippocampus in a mouse model of AD at 1, 6 and 12 months of age. Western blots and histoblots showed that the total amount of protein and the laminar expression pattern of GABAB1 were similar in APP/PS1 mice and in age-matched wild-type mice. In contrast, immunoelectron microscopic techniques showed that the subcellular localization of GABAB1 subunit did not change significantly in APP/PS1 mice at 1 month of age, was significantly reduced in the stratum lacunosum-moleculare of CA1 pyramidal cells at 6 months of age and significantly reduced at the membrane surface of CA1 pyramidal cells at 12 months of age. This reduction of plasma membrane GABAB1 was paralleled by a significant increase of the subunit at the intracellular sites. We further observed a decrease of membrane-targeted GABAB receptors in axon terminals contacting CA1 pyramidal cells. Our data demonstrate compartment- and age-dependent reduction of plasma membrane-targeted GABAB receptors in the CA1 region of the hippocampus, suggesting that this decrease might be enough to alter the GABAB -mediated synaptic transmission taking place in AD.
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Affiliation(s)
- Alejandro Martín-Belmonte
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Carolina Aguado
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Rocío Alfaro-Ruíz
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Ana Esther Moreno-Martínez
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Luis de la Ossa
- Departamento de Sistemas Informáticos, Escuela Superior de Ingeniería Informática, Universidad de Castilla-La Mancha, 02071, Albacete, Spain
| | - José Martínez-Hernández
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
| | - Alain Buisson
- Grenoble Institut des Neurosciences, Université Grenoble Alpes, BP 170, Grenoble, France
| | - Simon Früh
- Department of Biomedicine, Institute of Physiology, University of Basel, Basel, Switzerland
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, University of Basel, Basel, Switzerland
| | - Ryuichi Shigemoto
- Institute of Science and Technology (IST Austria), Am Campus 1, A-3400, Klosterneuburg, Austria
| | - Yugo Fukazawa
- Division of Brain Structure and Function, Faculty of Medical Science, University of Fukui, Fukui, Japan.,Life Science Innovation Center, University of Fukui, Fukui, Japan.,Research Center for Child Mental Development, Faculty of Medical Science, University of Fukui, Fukui, Japan
| | - Rafael Luján
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/ Almansa 14, 02008, Albacete, Spain
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20
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Mechanisms of GABA B receptor enhancement of extrasynaptic GABA A receptor currents in cerebellar granule cells. Sci Rep 2019; 9:16683. [PMID: 31723152 PMCID: PMC6853962 DOI: 10.1038/s41598-019-53087-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/26/2019] [Indexed: 12/31/2022] Open
Abstract
Many neurons, including cerebellar granule cells, exhibit a tonic GABA current mediated by extrasynaptic GABAA receptors. This current is a critical regulator of firing and the target of many clinically relevant compounds. Using a combination of patch clamp electrophysiology and photolytic uncaging of RuBi-GABA we show that GABAB receptors are tonically active and enhance extrasynaptic GABAA receptor currents in cerebellar granule cells. This enhancement is not associated with meaningful changes in GABAA receptor potency, mean channel open-time, open probability, or single-channel current. However, there was a significant (~40%) decrease in the number of channels participating in the GABA uncaging current and an increase in receptor desensitization. Furthermore, we find that adenylate cyclase, PKA, CaMKII, and release of Ca2+ from intracellular stores are necessary for modulation of GABAA receptors. Overall, this work reveals crosstalk between postsynaptic GABAA and GABAB receptors and identifies the signaling pathways and mechanisms involved.
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21
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Jin N, Lipponen A, Koivisto H, Gurevicius K, Tanila H. Increased cortical beta power and spike-wave discharges in middle-aged APP/PS1 mice. Neurobiol Aging 2018; 71:127-141. [PMID: 30138766 DOI: 10.1016/j.neurobiolaging.2018.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/12/2018] [Accepted: 07/14/2018] [Indexed: 12/11/2022]
Abstract
Amyloid plaque-forming transgenic mice display neuronal hyperexcitability, epilepsy, and sudden deaths in early adulthood. However, it is unknown whether hyperexcitability persists until middle ages when memory impairment manifests. We recorded multichannel video electroencephalography (EEG), local field potentials, and auditory evoked potentials in transgenic mice carrying mutated human amyloid precursor protein (APP) and presenilin-1 (PS1) genes and wild-type littermates at 14-16 months and compared the results with data we have earlier collected from 4-month-old mice. Furthermore, we monitored acoustic startle responses in other APP/PS1 and wild-type mice from 3 to 11 months of age. Independent of the age APP/PS1 mice demonstrated increased cortical power at 8-60 Hz. They also displayed over 5-fold increase in the occurrence of spike-wave discharges and augmented auditory evoked potentials compared with nontransgenic littermates. In contrast to evoked potentials, APP/PS1 mice showed normalization of acoustic startle responses with aging. Increased cortical power and spike-wave discharges provide powerful new biomarkers to monitor progression of amyloid pathology in preclinical intervention studies.
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Affiliation(s)
- Nanxiang Jin
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Arto Lipponen
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | | | | | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland.
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22
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Kulik Á, Booker SA, Vida I. Differential distribution and function of GABABRs in somato-dendritic and axonal compartments of principal cells and interneurons in cortical circuits. Neuropharmacology 2018; 136:80-91. [DOI: 10.1016/j.neuropharm.2017.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/12/2017] [Accepted: 10/13/2017] [Indexed: 12/24/2022]
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23
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Differential association of GABA B receptors with their effector ion channels in Purkinje cells. Brain Struct Funct 2017; 223:1565-1587. [PMID: 29177691 PMCID: PMC5869904 DOI: 10.1007/s00429-017-1568-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/10/2017] [Indexed: 11/23/2022]
Abstract
Metabotropic GABAB receptors mediate slow inhibitory effects presynaptically and postsynaptically through the modulation of different effector signalling pathways. Here, we analysed the distribution of GABAB receptors using highly sensitive SDS-digested freeze-fracture replica labelling in mouse cerebellar Purkinje cells. Immunoreactivity for GABAB1 was observed on presynaptic and, more abundantly, on postsynaptic compartments, showing both scattered and clustered distribution patterns. Quantitative analysis of immunoparticles revealed a somato-dendritic gradient, with the density of immunoparticles increasing 26-fold from somata to dendritic spines. To understand the spatial relationship of GABAB receptors with two key effector ion channels, the G protein-gated inwardly rectifying K+ (GIRK/Kir3) channel and the voltage-dependent Ca2+ channel, biochemical and immunohistochemical approaches were performed. Co-immunoprecipitation analysis demonstrated that GABAB receptors co-assembled with GIRK and CaV2.1 channels in the cerebellum. Using double-labelling immunoelectron microscopic techniques, co-clustering between GABAB1 and GIRK2 was detected in dendritic spines, whereas they were mainly segregated in the dendritic shafts. In contrast, co-clustering of GABAB1 and CaV2.1 was detected in dendritic shafts but not spines. Presynaptically, although no significant co-clustering of GABAB1 and GIRK2 or CaV2.1 channels was detected, inter-cluster distance for GABAB1 and GIRK2 was significantly smaller in the active zone than in the dendritic shafts, and that for GABAB1 and CaV2.1 was significantly smaller in the active zone than in the dendritic shafts and spines. Thus, GABAB receptors are associated with GIRK and CaV2.1 channels in different subcellular compartments. These data provide a better framework for understanding the different roles played by GABAB receptors and their effector ion channels in the cerebellar network.
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Fogerson PM, Huguenard JR. Tapping the Brakes: Cellular and Synaptic Mechanisms that Regulate Thalamic Oscillations. Neuron 2017; 92:687-704. [PMID: 27883901 DOI: 10.1016/j.neuron.2016.10.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/03/2016] [Accepted: 10/10/2016] [Indexed: 12/26/2022]
Abstract
Thalamic oscillators contribute to both normal rhythms associated with sleep and anesthesia and abnormal, hypersynchronous oscillations that manifest behaviorally as absence seizures. In this review, we highlight new findings that refine thalamic contributions to cortical rhythms and suggest that thalamic oscillators may be subject to both local and global control. We describe endogenous thalamic mechanisms that limit network synchrony and discuss how these protective brakes might be restored to prevent absence seizures. Finally, we describe how intrinsic and circuit-level specializations among thalamocortical loops may determine their involvement in widespread oscillations and render subsets of thalamic nuclei especially vulnerable to pathological synchrony.
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Affiliation(s)
- P Michelle Fogerson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Leresche N, Lambert RC. GABA receptors and T-type Ca 2+ channels crosstalk in thalamic networks. Neuropharmacology 2017; 136:37-45. [PMID: 28601398 DOI: 10.1016/j.neuropharm.2017.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/01/2017] [Accepted: 06/06/2017] [Indexed: 10/19/2022]
Abstract
Although the thalamus presents a rather limited repertoire of GABAergic cell types compare to other CNS area, this structure is a privileged system to study how GABA impacts neuronal network excitability. Indeed both glutamatergic thalamocortical (TC) and GABAergic nucleus reticularis thalami (NRT) neurons present a high expression of T-type voltage-dependent Ca2+ channels whose activation that shapes the output of the thalamus critically depends upon a preceding hyperpolarisation. Because of this strict dependence, a tight functional link between GABA mediated hyperpolarization and T-currents characterizes the thalamic network excitability. In this review we summarize a number of studies showing that the relationships between the various thalamic GABAA/B receptors and T-channels are complex and bidirectional. We discuss how this dynamic interaction sets the global intrathalamic network activity and its long-term plasticity and highlight how the functional relationship between GABA release and T-channel-dependent excitability is finely tuned by the T-channel activation itself. Finally, we illustrate how an impaired balance between T-channels and GABA receptors can lead to pathologically abnormal cellular and network behaviours. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Nathalie Leresche
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), 75005 Paris, France.
| | - Régis C Lambert
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), 75005 Paris, France
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Hamad M, Holland R, Kamal N, Luceri R, Mammis A. Potential for Intrathecal Baclofen in Treatment of Essential Tremor. World Neurosurg 2017; 105:170-175. [PMID: 28559069 DOI: 10.1016/j.wneu.2017.05.112] [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] [Received: 03/20/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Essential tremor (ET) is the most common movement disorder of adults, affecting an estimated 7 million Americans. Symptoms of ET range from slightly noticeable to debilitating, with 1 cohort study finding 15% of patients were forced into early retirement. Additionally, depression has also been correlated with the severity of disability of ET. Treatment options include propranolol and primidone. Current treatment options are not very effective, with more than half (56.3%) of patients discontinuing medications because of no changes in symptoms. METHODS Unfortunately, there is a relative void and controversy in the literature explaining ET pathophysiology; however, the gamma-aminobutyric acid (GABA) hypothesis is the strongest. We conducted a PubMed search on 30 September 2015 with no time constraints using the search terms "essential tremor" and "baclofen," which resulted in a total of 5 articles. RESULTS Neurohistopathologic studies have demonstrated decreased GABA-A and GABA-B receptors in the cerebellar cortex of ET patients. GABA, the major inhibitory neurotransmitter in the central nervous system, is proposed to have an inhibitory effect on pacemaker output activity of the cerebello-thalamo-cortical pathway, with lower receptors resulting in decreased inhibition of baseline tremors. Tariq et al showed delayed onset and intensity of tremor with oral administration of R-baclofen in a mouse model of ET. CONCLUSION With a better side-effect profile and success in a physiologically related condition, we propose more clinical trials and research be carried out on intrathecal baclofen as a potential treatment option, especially drug refractory ET, so as to increase the quality of life of this patient population.
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Affiliation(s)
- Mousa Hamad
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey, USA.
| | - Ryan Holland
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Naveed Kamal
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Robert Luceri
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Antonios Mammis
- Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey, USA
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Differential surface density and modulatory effects of presynaptic GABA B receptors in hippocampal cholecystokinin and parvalbumin basket cells. Brain Struct Funct 2017; 222:3677-3690. [PMID: 28466358 PMCID: PMC5676818 DOI: 10.1007/s00429-017-1427-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/13/2017] [Indexed: 12/27/2022]
Abstract
The perisomatic domain of cortical neurons is under the control of two major GABAergic inhibitory interneuron types: regular-spiking cholecystokinin (CCK) basket cells (BCs) and fast-spiking parvalbumin (PV) BCs. CCK and PV BCs are different not only in their intrinsic physiological, anatomical and molecular characteristics, but also in their presynaptic modulation of their synaptic output. Most GABAergic terminals are known to contain GABAB receptors (GABABR), but their role in presynaptic inhibition and surface expression have not been comparatively characterized in the two BC types. To address this, we performed whole-cell recordings from CCK and PV BCs and postsynaptic pyramidal cells (PCs), as well as freeze-fracture replica-based quantitative immunogold electron microscopy of their synapses in the rat hippocampal CA1 area. Our results demonstrate that while both CCK and PV BCs contain functional presynaptic GABABRs, their modulatory effects and relative abundance are markedly different at these two synapses: GABA release is dramatically inhibited by the agonist baclofen at CCK BC synapses, whereas a moderate reduction in inhibitory transmission is observed at PV BC synapses. Furthermore, GABABR activation has divergent effects on synaptic dynamics: paired-pulse depression (PPD) is enhanced at CCK BC synapses, but abolished at PV BC synapses. Consistent with the quantitative differences in presynaptic inhibition, virtually all CCK BC terminals were found to contain GABABRs at high densities, but only 40% of PV BC axon terminals contain GABABRs at detectable levels. These findings add to an increasing list of differences between these two interneuron types, with implications for their network functions.
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Leach K, Gregory KJ. Molecular insights into allosteric modulation of Class C G protein-coupled receptors. Pharmacol Res 2017; 116:105-118. [DOI: 10.1016/j.phrs.2016.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 11/18/2016] [Accepted: 12/07/2016] [Indexed: 12/23/2022]
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J. Onaolapo O, Y. Onaolapo A. The 21<sup>st</sup> Century Cerebellum: An Evolution of Cognitive Functions, Connections, Disorders, and Pharmacotherapeutic Modulation. AIMS Neurosci 2017. [DOI: 10.3934/neuroscience.2017.4.189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Loh KH, Stawski PS, Draycott AS, Udeshi ND, Lehrman EK, Wilton DK, Svinkina T, Deerinck TJ, Ellisman MH, Stevens B, Carr SA, Ting AY. Proteomic Analysis of Unbounded Cellular Compartments: Synaptic Clefts. Cell 2016; 166:1295-1307.e21. [PMID: 27565350 DOI: 10.1016/j.cell.2016.07.041] [Citation(s) in RCA: 247] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 05/16/2016] [Accepted: 07/26/2016] [Indexed: 10/21/2022]
Abstract
Cellular compartments that cannot be biochemically isolated are challenging to characterize. Here we demonstrate the proteomic characterization of the synaptic clefts that exist at both excitatory and inhibitory synapses. Normal brain function relies on the careful balance of these opposing neural connections, and understanding how this balance is achieved relies on knowledge of their protein compositions. Using a spatially restricted enzymatic tagging strategy, we mapped the proteomes of two of the most common excitatory and inhibitory synaptic clefts in living neurons. These proteomes reveal dozens of synaptic candidates and assign numerous known synaptic proteins to a specific cleft type. The molecular differentiation of each cleft allowed us to identify Mdga2 as a potential specificity factor influencing Neuroligin-2's recruitment of presynaptic neurotransmitters at inhibitory synapses.
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Affiliation(s)
- Ken H Loh
- Department of Chemistry, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Philipp S Stawski
- Department of Chemistry, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | - Austin S Draycott
- Department of Chemistry, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
| | | | - Emily K Lehrman
- F.M. Kirby Neurobiology Center, Boston Children's Hospital (BCH) and Harvard Medical School (HMS), Boston, MA 02115, USA
| | - Daniel K Wilton
- F.M. Kirby Neurobiology Center, Boston Children's Hospital (BCH) and Harvard Medical School (HMS), Boston, MA 02115, USA
| | - Tanya Svinkina
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Thomas J Deerinck
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, CA 92093 USA; Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, University of California at San Diego, La Jolla, CA 92093 USA; Department of Neurosciences, University of California at San Diego, La Jolla, CA 92093, USA
| | - Beth Stevens
- F.M. Kirby Neurobiology Center, Boston Children's Hospital (BCH) and Harvard Medical School (HMS), Boston, MA 02115, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Alice Y Ting
- Department of Chemistry, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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Halassa MM, Acsády L. Thalamic Inhibition: Diverse Sources, Diverse Scales. Trends Neurosci 2016; 39:680-693. [PMID: 27589879 DOI: 10.1016/j.tins.2016.08.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/31/2016] [Accepted: 08/02/2016] [Indexed: 12/11/2022]
Abstract
The thalamus is the major source of cortical inputs shaping sensation, action, and cognition. Thalamic circuits are targeted by two major inhibitory systems: the thalamic reticular nucleus (TRN) and extrathalamic inhibitory (ETI) inputs. A unifying framework of how these systems operate is currently lacking. Here, we propose that TRN circuits are specialized to exert thalamic control at different spatiotemporal scales. Local inhibition of thalamic spike rates prevails during attentional selection, whereas global inhibition more likely prevails during sleep. In contrast, the ETI (arising from basal ganglia, zona incerta (ZI), anterior pretectum, and pontine reticular formation) provides temporally precise and focal inhibition, impacting spike timing. Together, these inhibitory systems allow graded control of thalamic output, enabling thalamocortical operations to dynamically match ongoing behavioral demands.
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Affiliation(s)
- Michael M Halassa
- New York University Neuroscience Institute and the Departments of Psychiatry, Neuroscience and Physiology, New York University Langone Medical Center, New York, 10016, USA; Center for Neural Science, New York University, New York, 10016, USA.
| | - László Acsády
- Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, 1083 Hungary.
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Hannan S, Gerrow K, Triller A, Smart TG. Phospho-dependent Accumulation of GABABRs at Presynaptic Terminals after NMDAR Activation. Cell Rep 2016; 16:1962-73. [PMID: 27498877 PMCID: PMC4987283 DOI: 10.1016/j.celrep.2016.07.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/19/2016] [Accepted: 07/09/2016] [Indexed: 11/24/2022] Open
Abstract
Here, we uncover a mechanism for regulating the number of active presynaptic GABAB receptors (GABABRs) at nerve terminals, an important determinant of neurotransmitter release. We find that GABABRs gain access to axon terminals by lateral diffusion in the membrane. Their relative accumulation is dependent upon agonist activation and the presence of the two distinct sushi domains that are found only in alternatively spliced GABABR1a subunits. Following brief activation of NMDA receptors (NMDARs) using glutamate, GABABR diffusion is reduced, causing accumulation at presynaptic terminals in a Ca(2+)-dependent manner that involves phosphorylation of GABABR2 subunits at Ser783. This signaling cascade indicates how synaptically released glutamate can initiate, via a feedback mechanism, increased levels of presynaptic GABABRs that limit further glutamate release and excitotoxicity.
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Affiliation(s)
- Saad Hannan
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Kim Gerrow
- Biologie Cellulaire de la Synapse, Inserm U1024, Institute of Biology, École Normale Supérieure (ENS), 46 rue d'Ulm, Paris 75005, France
| | - Antoine Triller
- Biologie Cellulaire de la Synapse, Inserm U1024, Institute of Biology, École Normale Supérieure (ENS), 46 rue d'Ulm, Paris 75005, France
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
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Howell RD, Pugh JR. Biphasic modulation of parallel fibre synaptic transmission by co-activation of presynaptic GABAA and GABAB receptors in mice. J Physiol 2016; 594:3651-66. [PMID: 27061582 DOI: 10.1113/jp272124] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/30/2016] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS Many excitatory synapses co-express presynaptic GABAA and GABAB receptors, despite their opposing actions on synaptic transmission. It is still unclear how co-activation of these receptors modulates synapse function. We measured presynaptic GABA receptor function at parallel fibre synapses onto stellate cells in the cerebellum using whole-cell patch-clamp recording and photolytic uncaging of RuBi-GABA. Activation of presynaptic GABA receptors results in a transient (∼100 ms) enhancement of synaptic transmission (mediated by GABAA receptors) followed by a long lasting (>500 ms) inhibition of transmission (mediated by GABAB receptors). When activated just prior to high-frequency trains of stimulation, presynaptic GABAA and GABAB receptors work together to reduce short-term facilitation/enhance depression, altering the filtering properties of synaptic transmission. Inhibition of synaptic transmission by GABAB receptors is more sensitive to GABA than enhancement by GABAA receptors, suggesting GABAB receptors may be activated by ambient GABA or release from greater distances. ABSTRACT GABAA and GABAB receptors are co-expressed at many presynaptic terminals in the central nervous system. Previous studies have shown that GABAA receptors typically enhance vesicle release while GABAB receptors inhibit release. However, it is not clear how the competing actions of these receptors modulate synaptic transmission when co-activated, as is likely in vivo. We investigated this question at parallel fibre synapses in the cerebellum, which co-express presynaptic GABAA and GABAB receptors. In acute slices from C57BL/6 mice, we find that co-activation of presynaptic GABA receptors by photolytic uncaging of RuBi-GABA has a biphasic effect on EPSC amplitudes recorded from stellate cells. Synchronous and asynchronous EPSCs evoked within ∼100 ms of GABA uncaging were increased, while EPSCs evoked ∼300-600 ms after GABA uncaging were reduced compared to interleaved control sweeps. We confirmed these effects are presynaptic by measuring the paired-pulse ratio, variance of EPSC amplitudes, and response probability. During trains of high-frequency stimulation GABAA and GABAB receptors work together (rather than oppose one another) to reduce short-term facilitation when GABA is uncaged just prior to the onset of stimulation. We also find that GABAB receptor-mediated inhibition can be elicited by lower GABA concentrations than GABAA receptor-mediated enhancement of EPSCs, suggesting GABAB receptors may be selectively activated by ambient GABA or release from more distance synapses. These data suggest that GABA, acting through both presynaptic GABAA and GABAB receptors, modulate the amplitude and short-term plasticity of excitatory synapses, a result not possible from activation of either receptor type alone.
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Affiliation(s)
- Rebecca D Howell
- University of Texas Health Science Center at San Antonio, Department of Physiology, San Antonio, TX 78229, USA
| | - Jason R Pugh
- University of Texas Health Science Center at San Antonio, Department of Physiology, San Antonio, TX 78229, USA
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Booker SA, Althof D, Gross A, Loreth D, Müller J, Unger A, Fakler B, Varro A, Watanabe M, Gassmann M, Bettler B, Shigemoto R, Vida I, Kulik Á. KCTD12 Auxiliary Proteins Modulate Kinetics of GABABReceptor-Mediated Inhibition in Cholecystokinin-Containing Interneurons. Cereb Cortex 2016; 27:2318-2334. [DOI: 10.1093/cercor/bhw090] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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35
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Bragina L, Bonifacino T, Bassi S, Milanese M, Bonanno G, Conti F. Differential expression of metabotropic glutamate and GABA receptors at neocortical glutamatergic and GABAergic axon terminals. Front Cell Neurosci 2015; 9:345. [PMID: 26388733 PMCID: PMC4559644 DOI: 10.3389/fncel.2015.00345] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/18/2015] [Indexed: 12/04/2022] Open
Abstract
Metabotropic glutamate (Glu) receptors (mGluRs) and GABAB receptors are highly expressed at presynaptic sites. To verify the possibility that the two classes of metabotropic receptors contribute to axon terminals heterogeneity, we studied the localization of mGluR1α, mGluR5, mGluR2/3, mGluR7, and GABAB1 in VGLUT1-, VGLUT2-, and VGAT- positive terminals in the cerebral cortex of adult rats. VGLUT1-positive puncta expressed mGluR1α (∼5%), mGluR5 (∼6%), mGluR2/3 (∼22%), mGluR7 (∼17%), and GABAB1 (∼40%); VGLUT2-positive terminals expressed mGluR1α (∼10%), mGluR5 (∼11%), mGluR2/3 (∼20%), mGluR7 (∼28%), and GABAB1 (∼25%); whereas VGAT-positive puncta expressed mGluR1α (∼27%), mGluR5 (∼24%), mGluR2/3 (∼38%), mGluR7 (∼31%), and GABAB1 (∼19%). Control experiments ruled out the possibility that postsynaptic mGluRs and GABAB1 might have significantly biased our results. We also performed functional assays in synaptosomal preparations, and showed that all agonists modify Glu and GABA levels, which return to baseline upon exposure to antagonists. Overall, these findings indicate that mGluR1α, mGluR5, mGluR2/3, mGluR7, and GABAB1 expression differ significantly between glutamatergic and GABAergic axon terminals, and that the robust expression of heteroreceptors may contribute to the homeostatic regulation of the balance between excitation and inhibition.
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Affiliation(s)
- Luca Bragina
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle MarcheAncona, Italy
- Center for Neurobiology of Aging, Istituto Nazionale di Riposo e Cura per Anziani – Istituto di Ricovero e Cura a Carattere ScientificoAncona, Italy
| | - Tiziana Bonifacino
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of GenoaGenoa, Italy
| | - Silvia Bassi
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle MarcheAncona, Italy
| | - Marco Milanese
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of GenoaGenoa, Italy
| | - Giambattista Bonanno
- Department of Pharmacy, Unit of Pharmacology and Toxicology, University of GenoaGenoa, Italy
- Center of Excellence for Biomedical Research, University of GenoaGenoa, Italy
| | - Fiorenzo Conti
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle MarcheAncona, Italy
- Center for Neurobiology of Aging, Istituto Nazionale di Riposo e Cura per Anziani – Istituto di Ricovero e Cura a Carattere ScientificoAncona, Italy
- Fondazione di Medicina Molecolare, Università Politecnica delle MarcheAncona, Italy
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Nakadate K, Tanaka-Nakadate S. Three-Dimensional Electron Microscopy Reconstruction of Degenerative Dopaminergic Neurons Surrounded by Activated Microglia in Substantia Nigra. Ultrastruct Pathol 2015; 39:369-77. [PMID: 26111207 DOI: 10.3109/01913123.2015.1042609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There is an urgent need to investigate the reason for the pathogenic mechanism of intractable central neurological diseases such as Parkinson's disease. It has been reported that the activation of microglial cells is involved in the pathology of these diseases. However, due to technical difficulties, the relationship between degenerative neurons and activated microglial cells remains unclear. Therefore, we tried the improved analysis technique to clarify the spatial relationship between these cell types. We were able to establish an analysis technique that consists of a three-dimensional reconstruction method using serial immunoelectron micrographs after having identified both degenerative neurons and activated microglial cells under optical microscope. Using this technique, we have relatively easily been able to clarify the spatial relationship between degenerative neurons and activated microglial cells. Furthermore, using this technique it is possible to determine the neuronal degeneration process in detail, because it is able to identify structures implicated in degeneration, such as accumulation of lipofuscin in degenerated neuronal somata and phagocytotic structures of microglial cells. In future, this technical approach may be applied to elucidate the relationship between degenerative neurons and activated glial cells in human diseases.
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Affiliation(s)
- Kazuhiko Nakadate
- a Department of Basic Science , Educational and Research Center for Pharmacy, Meiji Pharmaceutical University , Tokyo , Japan and
| | - Sawako Tanaka-Nakadate
- b Department of Pharmacology and Toxicology , Dokkyo Medical University School of Medicine , Tochigi , Japan
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Li MH, Suchland KL, Ingram SL. GABAergic transmission and enhanced modulation by opioids and endocannabinoids in adult rat rostral ventromedial medulla. J Physiol 2014; 593:217-30. [PMID: 25556797 DOI: 10.1113/jphysiol.2014.275701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 10/17/2014] [Indexed: 01/24/2023] Open
Abstract
KEY POINTS Electrical stimulation of the rostral ventromedial medulla (RVM) facilitates pain behaviours in neonates but inhibits these behaviours in adults. The cellular mechanisms underlying these changes in RVM modulation of pain behaviours are not known. We optimized whole-cell patch-clamp recordings for RVM neurons in animals older than postnatal day 30 and compared the results to postnatal day 10-21 animals. Our results demonstrate that the γ-aminobutyric acid (GABA) release is lower and opioid effects are more evident in adult rats compared to early postnatal rats. A cannabinoid receptor antagonist significantly increased GABA release in mature but not in immature RVM neurons suggesting the presence of local endocannabinoid tone in mature RVM. Neurons in the rostral ventromedial medulla (RVM) play critical and complex roles in pain modulation. Recent studies have shown that electrical stimulation of the RVM produces pain facilitation in young animals (postnatal (PN) day < 21) but predominantly inhibits pain behaviours in adults. The cellular mechanisms underlying these changes in RVM modulation of pain behaviours are not known. This is in part because whole-cell patch-clamp studies in RVM to date have been in young (PN day < 18) animals because the organization and abundance of myelinated fibres in this region make the RVM a challenging area for whole-cell patch-clamp recording in adults. Several neurotransmitter systems, including GABAergic neurotransmission, undergo developmental changes that mature by PN day 21. Thus, we focused on optimizing whole-cell patch-clamp recordings for RVM neurons in animals older than PN day 30 and compared the results to animals at PN day 10-21. Our results demonstrate that the probability of GABA release is lower and that opioid and endocannabinoid effects are more evident in adult rats (mature) compared to early postnatal (immature) rats. Differences in these properties of RVM neurons may contribute to the developmental changes in descending control of pain from the RVM to the spinal cord.
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Affiliation(s)
- Ming-Hua Li
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR, 97239, USA
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Joint CP-AMPA and group I mGlu receptor activation is required for synaptic plasticity in dentate gyrus fast-spiking interneurons. Proc Natl Acad Sci U S A 2014; 111:13211-6. [PMID: 25161282 DOI: 10.1073/pnas.1409394111] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hippocampal principal cell (PC) assemblies provide the brain with a mnemonic representation of space. It is assumed that the formation of cell assemblies is supported by long-lasting modification of glutamatergic synapses onto perisomatic inhibitory interneurons (PIIs), which provide powerful feedback inhibition to neuronal networks. Repetitive activation of dentate gyrus PIIs by excitatory mossy fiber (MF) inputs induces Hebbian long-term potentiation (LTP). In contrast, long-term depression (LTD) emerges in the absence of PII activity. However, little is known about the molecular mechanisms underlying synaptic plasticity in PIIs. Here, we examined the role of group I metabotropic glutamate receptors 1 and 5 (mGluRs1/5) in inducing plastic changes at MF-PII synapses. We found that mGluRs1/5 are located perisynaptically and that pharmacological block of mGluR1 or mGluR5 abolished MF-LTP. In contrast, their exogenous activation was insufficient to induce MF-LTP but cleared MF-LTD. No LTP could be elicited in PIIs loaded with blockers of G protein signaling and Ca(2+)-dependent PKC. Two-photon imaging revealed that the intracellular Ca(2+) rise necessary for MF-LTP was largely mediated by Ca(2+)-permeable AMPA receptors (CP-AMPARs), but less by NMDA receptors or mGluRs1/5. Thus, our data indicate that fast Ca(2+) signaling via CP-AMPARs and slow G protein-mediated signaling via mGluRs1/5 converge to a PKC-dependent molecular pathway to induce Hebbian MF-LTP. We further propose that Hebbian activation of mGluRs1/5 gates PIIs into a "readiness mode" to promote MF-LTP, which, in turn, will support timed PII recruitment, thereby assisting in PC assembly formation.
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39
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Park A, Hoffman K, Keller A. Roles of GABAA and GABAB receptors in regulating thalamic activity by the zona incerta: a computational study. J Neurophysiol 2014; 112:2580-96. [PMID: 25143541 DOI: 10.1152/jn.00282.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The posterior thalamic nucleus (PO) is a higher order nucleus heavily implicated in the processing of somatosensory information. We have previously shown in rodent models that activity in PO is tightly regulated by inhibitory inputs from a GABAergic nucleus known as the zona incerta (ZI). The level of incertal inhibition varies under both physiological and pathological conditions, leading to concomitant changes in PO activity. These changes are causally linked to variety of phenomena from altered sensory perception to pathological pain. ZI regulation of PO is mediated by GABAA and GABAB receptors (GABAAR and GABABR) that differ in their binding kinetics and their electrophysiological properties, suggesting that each may have distinct roles in incerto-thalamic regulation. We developed a computational model to test this hypothesis. We created a two-cell Hodgkin-Huxley model representing PO and ZI with kinetically realistic GABAAR- and GABABR-mediated synapses. We simulated spontaneous and evoked firing in PO and observed how these activities were affected by inhibition mediated by each receptor type. Our model predicts that spontaneous PO activity is preferentially regulated by GABABR-mediated mechanisms, while evoked activity is preferentially regulated by GABAAR. Our model also predicts that modulation of ZI firing rate and synaptic GABA concentrations is an effective means to regulate the incerto-thalamic circuit. The coupling of distinct functions to GABAAR and GABABR presents an opportunity for the development of therapeutics, as particular aspects of incerto-thalamic regulation can be targeted by manipulating the corresponding receptor class. Thus these findings may provide interventions for pathologies of sensory processing.
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Affiliation(s)
- Anthony Park
- Program in Neuroscience, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Kathleen Hoffman
- Department of Mathematics and Statistics, University of Maryland Baltimore County, Baltimore, Maryland
| | - Asaf Keller
- Program in Neuroscience, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland; and
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40
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The timing of dopamine- and noradrenaline-mediated transmission reflects underlying differences in the extent of spillover and pooling. J Neurosci 2014; 34:7645-56. [PMID: 24872568 DOI: 10.1523/jneurosci.0166-14.2014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Metabotropic transmission typically occurs through the spillover activation of extrasynaptic receptors. This study examined the mechanisms underlying somatodendritic dopamine and noradrenaline transmission and found that the extent of spillover and pooling varied dramatically between these two transmitters. In the mouse ventral tegmental area, the time course of D2-receptor-mediated IPSCs (D2-IPSCs) was consistent between cells and was unaffected by altering stimulation intensity, probability of release, or the extent of diffusion. Blocking dopamine reuptake with cocaine extended the time course of D2-IPSCs and suggested that transporters strongly limited spillover. As a result, individual release sites contributed independently to the duration of D2-IPSCs. In contrast, increasing the release of noradrenaline in the rat locus ceruleus prolonged the duration of α2-receptor-mediated IPSCs even when reuptake was intact. Spillover and subsequent pooling of noradrenaline activated distal α2-receptors, which prolonged the duration of α2-IPSCs when multiple release sites were activated synchronously. By using the rapid application of agonists onto large macropatches, we determined the concentration profile of agonists underlying the two IPSCs. Incorporating the results into a model simulating extracellular diffusion predicted that the functional range of noradrenaline diffusion was nearly fivefold greater in the locus ceruleus than dopamine in the midbrain. This study demonstrates that catecholamine synapses differentially regulate the extent of spillover and pooling to control the timing of local inhibition and suggests diversity in the roles of uptake and diffusion in governing metabotropic transmission.
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41
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Rubio ME, Fukazawa Y, Kamasawa N, Clarkson C, Molnár E, Shigemoto R. Target- and input-dependent organization of AMPA and NMDA receptors in synaptic connections of the cochlear nucleus. J Comp Neurol 2014; 522:4023-42. [PMID: 25041792 DOI: 10.1002/cne.23654] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 07/07/2014] [Accepted: 07/17/2014] [Indexed: 12/12/2022]
Abstract
We examined the synaptic structure, quantity, and distribution of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)- and N-methyl-D-aspartate (NMDA)-type glutamate receptors (AMPARs and NMDARs, respectively) in rat cochlear nuclei by a highly sensitive freeze-fracture replica labeling technique. Four excitatory synapses formed by two distinct inputs, auditory nerve (AN) and parallel fibers (PF), on different cell types were analyzed. These excitatory synapse types included AN synapses on bushy cells (AN-BC synapses) and fusiform cells (AN-FC synapses) and PF synapses on FC (PF-FC synapses) and cartwheel cell spines (PF-CwC synapses). Immunogold labeling revealed differences in synaptic structure as well as AMPAR and NMDAR number and/or density in both AN and PF synapses, indicating a target-dependent organization. The immunogold receptor labeling also identified differences in the synaptic organization of FCs based on AN or PF connections, indicating an input-dependent organization in FCs. Among the four excitatory synapse types, the AN-BC synapses were the smallest and had the most densely packed intramembrane particles (IMPs), whereas the PF-CwC synapses were the largest and had sparsely packed IMPs. All four synapse types showed positive correlations between the IMP-cluster area and the AMPAR number, indicating a common intrasynapse-type relationship for glutamatergic synapses. Immunogold particles for AMPARs were distributed over the entire area of individual AN synapses; PF synapses often showed synaptic areas devoid of labeling. The gold-labeling for NMDARs occurred in a mosaic fashion, with less positive correlations between the IMP-cluster area and the NMDAR number. Our observations reveal target- and input-dependent features in the structure, number, and organization of AMPARs and NMDARs in AN and PF synapses.
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Affiliation(s)
- María E Rubio
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh, PA, USA
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42
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Hawkes R. Purkinje cell stripes and long-term depression at the parallel fiber-Purkinje cell synapse. Front Syst Neurosci 2014; 8:41. [PMID: 24734006 PMCID: PMC3975104 DOI: 10.3389/fnsys.2014.00041] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/07/2014] [Indexed: 12/13/2022] Open
Abstract
The cerebellar cortex comprises a stereotyped array of transverse zones and parasagittal stripes, built around multiple Purkinje cell subtypes, which is highly conserved across birds and mammals. This architecture is revealed in the restricted expression patterns of numerous molecules, in the terminal fields of the afferent projections, in the distribution of interneurons, and in the functional organization. This review provides an overview of cerebellar architecture with an emphasis on attempts to relate molecular architecture to the expression of long-term depression (LTD) at the parallel fiber-Purkinje cell (pf-PC) synapse.
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Affiliation(s)
- Richard Hawkes
- Department of Cell Biology and Anatomy, University of Calgary Calgary, AB, Canada ; Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Genes and Development Research Group, Faculty of Medicine, University of Calgary Calgary, AB, Canada
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43
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Mapelli L, Solinas S, D'Angelo E. Integration and regulation of glomerular inhibition in the cerebellar granular layer circuit. Front Cell Neurosci 2014; 8:55. [PMID: 24616663 PMCID: PMC3933946 DOI: 10.3389/fncel.2014.00055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/06/2014] [Indexed: 11/26/2022] Open
Abstract
Inhibitory synapses can be organized in different ways and be regulated by a multitude of mechanisms. One of the best known examples is provided by the inhibitory synapses formed by Golgi cells onto granule cells in the cerebellar glomeruli. These synapses are GABAergic and inhibit granule cells through two main mechanisms, phasic and tonic. The former is based on vesicular neurotransmitter release, the latter on the establishment of tonic γ-aminobutyric acid (GABA) levels determined by spillover and regulation of GABA uptake. The mechanisms of post-synaptic integration have been clarified to a considerable extent and have been shown to differentially involve α1 and α6 subunit-containing GABA-A receptors. Here, after reviewing the basic mechanisms of GABAergic transmission in the cerebellar glomeruli, we examine how inhibition controls signal transfer at the mossy fiber-granule cell relay. First of all, we consider how vesicular release impacts on signal timing and how tonic GABA levels control neurotransmission gain. Then, we analyze the integration of these inhibitory mechanisms within the granular layer network. Interestingly, it turns out that glomerular inhibition is just one element in a large integrated signaling system controlled at various levels by metabotropic receptors. GABA-B receptor activation by ambient GABA regulates glutamate release from mossy fibers through a pre-synaptic cross-talk mechanisms, GABA release through pre-synaptic auto-receptors, and granule cell input resistance through post-synaptic receptor activation and inhibition of a K inward-rectifier current. Metabotropic glutamate receptors (mGluRs) control GABA release from Golgi cell terminals and Golgi cell input resistance and autorhythmic firing. This complex set of mechanisms implements both homeostatic and winner-take-all processes, providing the basis for fine-tuning inhibitory neurotransmission and for optimizing signal transfer through the cerebellar cortex.
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Affiliation(s)
- Lisa Mapelli
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy
- Brain Connectivity Center, C. Mondino National Neurological InstitutePavia, Italy
| | - Sergio Solinas
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy
- Brain Connectivity Center, C. Mondino National Neurological InstitutePavia, Italy
| | - Egidio D'Angelo
- Department of Brain and Behavioral Sciences, University of PaviaPavia, Italy
- Brain Connectivity Center, C. Mondino National Neurological InstitutePavia, Italy
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44
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Winkelmann A, Maggio N, Eller J, Caliskan G, Semtner M, Häussler U, Jüttner R, Dugladze T, Smolinsky B, Kowalczyk S, Chronowska E, Schwarz G, Rathjen FG, Rechavi G, Haas CA, Kulik A, Gloveli T, Heinemann U, Meier JC. Changes in neural network homeostasis trigger neuropsychiatric symptoms. J Clin Invest 2014; 124:696-711. [PMID: 24430185 PMCID: PMC3904623 DOI: 10.1172/jci71472] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 10/31/2013] [Indexed: 12/13/2022] Open
Abstract
The mechanisms that regulate the strength of synaptic transmission and intrinsic neuronal excitability are well characterized; however, the mechanisms that promote disease-causing neural network dysfunction are poorly defined. We generated mice with targeted neuron type-specific expression of a gain-of-function variant of the neurotransmitter receptor for glycine (GlyR) that is found in hippocampectomies from patients with temporal lobe epilepsy. In this mouse model, targeted expression of gain-of-function GlyR in terminals of glutamatergic cells or in parvalbumin-positive interneurons persistently altered neural network excitability. The increased network excitability associated with gain-of-function GlyR expression in glutamatergic neurons resulted in recurrent epileptiform discharge, which provoked cognitive dysfunction and memory deficits without affecting bidirectional synaptic plasticity. In contrast, decreased network excitability due to gain-of-function GlyR expression in parvalbumin-positive interneurons resulted in an anxiety phenotype, but did not affect cognitive performance or discriminative associative memory. Our animal model unveils neuron type-specific effects on cognition, formation of discriminative associative memory, and emotional behavior in vivo. Furthermore, our data identify a presynaptic disease-causing molecular mechanism that impairs homeostatic regulation of neural network excitability and triggers neuropsychiatric symptoms.
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Affiliation(s)
- Aline Winkelmann
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Nicola Maggio
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Joanna Eller
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Gürsel Caliskan
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Marcus Semtner
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Ute Häussler
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - René Jüttner
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Tamar Dugladze
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Birthe Smolinsky
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Sarah Kowalczyk
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Ewa Chronowska
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Günter Schwarz
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Fritz G. Rathjen
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Gideon Rechavi
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Carola A. Haas
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Akos Kulik
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Tengis Gloveli
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Uwe Heinemann
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Jochen C. Meier
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
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45
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Shirai Y, Sasajima T, Uchiyama S, Takegoshi Y, Tsushima E, Tabata T. [Activation of cerebellar B-type γ-aminobutyric acid receptor modulates optokinetic reflex adaptation]. YAKUGAKU ZASSHI 2013; 134:439-45. [PMID: 24304601 DOI: 10.1248/yakushi.13-00233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cerebellar cortex, the brain region responsible for motor coordination and learning expresses a high density of B-type γ-aminobutyric acid receptor (GABAbR). Previous in vitro and in situ studies indicated that cerebellar GABAbR may mediate multiple forms of inhibitory and excitatory modulation of cerebellar circuits. Nevertheless, the in vivo influence of cerebellar GABAbR activation is unclear. As the first step in addressing this issue, we examined how pharmacological activation of cerebellar GABAbR modulates optokinetic reflex (OKR), an involuntary cerebellum-dependent eye movement for stabilizing the retinal image against the drift of the visual scene. We injected baclofen, a GABAbR-selective agonist, or control saline into the cerebellar flocculi of adult mice and then performed 1-h OKR measurement sessions on two consecutive days. In the day 1 session, the baclofen (5 nM)-injected mice and control mice showed similar initial OKR gains and similar training-induced increases in the OKR gain (OKR adaptation). This result suggests that GABAbR activation does not affect cerebellar computation for executing OKR and formation of short-term memory for OKR adaptation. At the beginning of the day 2 session, the baclofen (5 nM or 50 μM)-injected mice showed an OKR gain higher than that achieved in the day 1 session while the control mice did not. This result suggests that GABAbR activation may facilitate the formation of OKR adaptation-related long-term memory. These findings provide a new insight into the functional architecture of the cerebellar circuits and indicate GABAbR to be a new target of pharmacological therapy against diseases with cerebellar dysfunction.
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Affiliation(s)
- Yoshihiro Shirai
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama
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46
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Ehrlich DE, Ryan SJ, Hazra R, Guo JD, Rainnie DG. Postnatal maturation of GABAergic transmission in the rat basolateral amygdala. J Neurophysiol 2013; 110:926-41. [PMID: 23719209 PMCID: PMC3742982 DOI: 10.1152/jn.01105.2012] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 05/28/2013] [Indexed: 12/12/2022] Open
Abstract
Many psychiatric disorders, including anxiety and autism spectrum disorders, have early ages of onset and high incidence in juveniles. To better treat and prevent these disorders, it is important to first understand normal development of brain circuits that process emotion. Healthy and maladaptive emotional processing involve the basolateral amygdala (BLA), dysfunction of which has been implicated in numerous psychiatric disorders. Normal function of the adult BLA relies on a fine balance of glutamatergic excitation and GABAergic inhibition. Elsewhere in the brain GABAergic transmission changes throughout development, but little is known about the maturation of GABAergic transmission in the BLA. Here we used whole cell patch-clamp recording and single-cell RT-PCR to study GABAergic transmission in rat BLA principal neurons at postnatal day (P)7, P14, P21, P28, and P35. GABAA currents exhibited a significant twofold reduction in rise time and nearly 25% reduction in decay time constant between P7 and P28. This corresponded with a shift in expression of GABAA receptor subunit mRNA from the α2- to the α1-subunit. The reversal potential for GABAA receptors transitioned from depolarizing to hyperpolarizing with age, from around -55 mV at P7 to -70 mV by P21. There was a corresponding shift in expression of opposing chloride pumps that influence the reversal, from NKCC1 to KCC2. Finally, we observed short-term depression of GABAA postsynaptic currents in immature neurons that was significantly and gradually abolished by P28. These findings reveal that in the developing BLA GABAergic transmission is highly dynamic, reaching maturity at the end of the first postnatal month.
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Affiliation(s)
- David E Ehrlich
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia 30329, USA
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47
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Differential GABAB-receptor-mediated effects in perisomatic- and dendrite-targeting parvalbumin interneurons. J Neurosci 2013; 33:7961-74. [PMID: 23637187 DOI: 10.1523/jneurosci.1186-12.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Inhibitory parvalbumin-containing interneurons (PVIs) control neuronal discharge and support the generation of theta- and gamma-frequency oscillations in cortical networks. Fast GABAergic input onto PVIs is crucial for their synchronization and oscillatory entrainment, but the role of metabotropic GABA(B) receptors (GABA(B)Rs) in mediating slow presynaptic and postsynaptic inhibition remains unknown. In this study, we have combined high-resolution immunoelectron microscopy, whole-cell patch-clamp recording, and computational modeling to investigate the subcellular distribution and effects of GABA(B)Rs and their postsynaptic effector Kir3 channels in rat hippocampal PVIs. Pre-embedding immunogold labeling revealed that the receptors and channels localize at high levels to the extrasynaptic membrane of parvalbumin-immunoreactive dendrites. Immunoreactivity for GABA(B)Rs was also present at lower levels on PVI axon terminals. Whole-cell recordings further showed that synaptically released GABA in response to extracellular stimulation evokes large GABA(B)R-mediated slow IPSCs in perisomatic-targeting (PT) PVIs, but only small or no currents in dendrite-targeting (DT) PVIs. In contrast, paired recordings demonstrated that GABA(B)R activation results in presynaptic inhibition at the output synapses of both PT and DT PVIs, but more strongly in the latter. Finally, computational analysis indicated that GABA(B) IPSCs can phasically modulate the discharge of PT interneurons at theta frequencies. In summary, our results show that GABA(B)Rs differentially mediate slow presynaptic and postsynaptic inhibition in PVIs and can contribute to the dynamic modulation of their activity during oscillations. Furthermore, these data provide evidence for a compartment-specific molecular divergence of hippocampal PVI subtypes, suggesting that activation of GABA(B)Rs may shift the balance between perisomatic and dendritic inhibition.
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48
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Nakajima C, Kulik A, Frotscher M, Herz J, Schäfer M, Bock HH, May P. Low density lipoprotein receptor-related protein 1 (LRP1) modulates N-methyl-D-aspartate (NMDA) receptor-dependent intracellular signaling and NMDA-induced regulation of postsynaptic protein complexes. J Biol Chem 2013; 288:21909-23. [PMID: 23760271 DOI: 10.1074/jbc.m112.444364] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lipoprotein receptor LRP1 is essential in neurons of the central nervous system, as was revealed by the analysis of conditional Lrp1-deficient mouse models. The molecular basis of its neuronal functions, however, is still incompletely understood. Here we show by immunocytochemistry, electron microscopy, and postsynaptic density preparation that LRP1 is located postsynaptically. Basal and NMDA-induced phosphorylation of the transcription factor cAMP-response element-binding protein (CREB) as well as NMDA target gene transcription are reduced in LRP1-deficient neurons. In control neurons, NMDA promotes γ-secretase-dependent release of the LRP1 intracellular domain (LRP1-ICD). However, pull-down and chromatin immunoprecipitation (ChIP) assays showed no direct interaction between the LRP1-ICD and either CREB or target gene promoters. On the other hand, NMDA-induced degradation of the postsynaptic scaffold protein PSD-95 was impaired in the absence of LRP1, whereas its ubiquitination was increased, indicating that LRP1 influences the composition of postsynaptic protein complexes. Accordingly, NMDA-induced internalization of the AMPA receptor subunit GluA1 was impaired in LRP1-deficient neurons. These results show a role of LRP1 in the regulation and turnover of synaptic proteins, which may contribute to the reduced dendritic branching and to the neurological phenotype observed in the absence of LRP1.
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Affiliation(s)
- Chikako Nakajima
- Department of Medicine II, University Hospital and University of Freiburg, 79104 Freiburg, Germany
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49
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Species differences in somatodendritic dopamine transmission determine D2-autoreceptor-mediated inhibition of ventral tegmental area neuron firing. J Neurosci 2012; 32:13520-8. [PMID: 23015441 DOI: 10.1523/jneurosci.2745-12.2012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The somatodendritic release of dopamine within the ventral tegmental area (VTA) and substantia nigra pars compacta activates inhibitory postsynaptic D2-receptors on dopaminergic neurons. The proposed mechanisms that regulate this form of transmission differ between electrochemical studies using rats and guinea pigs and electrophysiological studies using mice. This study examines the release and resulting dopamine D2-autoreceptor-mediated IPSCs (D2-IPSCs) in the VTA of mouse, rat, and guinea pig. Robust D2-IPSCs were observed in all recordings from neurons in slices taken from mouse, whereas D2-IPSCs in rat and guinea pig were observed less frequently and were significantly smaller in amplitude. In slices taken from guinea pig, dopamine release was more persistent under conditions of reduced extracellular calcium. The decline in the concentration of dopamine was also prolonged and not as sensitive to inhibition of reuptake by cocaine. This resulted in an increased duration of D2-IPSCs in the guinea pig. Therefore, unlike the mouse or the rat, the time course of dopamine in the extracellular space of the guinea pig determined the duration the D2-IPSC. Functionally, differences in D2-IPSCs resulted in inhibition of dopamine neuron firing only in slices from mouse. The results suggest that the mechanisms and functional consequences of somatodendritic dopamine transmission in the VTA vary among species. This highlights the complexity that underlies dopamine-dependent transmission in one brain area. Differences in somatodendritic transmission would be expected in vivo to affect the downstream activity of the mesocorticolimbic dopamine system and subsequent terminal release.
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50
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GABAergic inhibition of histaminergic neurons regulates active waking but not the sleep-wake switch or propofol-induced loss of consciousness. J Neurosci 2012; 32:13062-75. [PMID: 22993424 DOI: 10.1523/jneurosci.2931-12.2012] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The activity of histaminergic neurons in the tuberomammillary nucleus (TMN) of the hypothalamus correlates with an animal's behavioral state and maintains arousal. We examined how GABAergic inputs onto histaminergic neurons regulate this behavior. A prominent hypothesis, the "flip-flop" model, predicts that increased and sustained GABAergic drive onto these cells promotes sleep. Similarly, because of the histaminergic neurons' key hub-like place in the arousal circuitry, it has also been suggested that anesthetics such as propofol induce loss of consciousness by acting primarily at histaminergic neurons. We tested both these hypotheses in mice by genetically removing ionotropic GABA(A) or metabotropic GABA(B) receptors from histidine decarboxylase-expressing neurons. At the cellular level, histaminergic neurons deficient in synaptic GABA(A) receptors were significantly more excitable and were insensitive to the anesthetic propofol. At the behavioral level, EEG profiles were recorded in nontethered mice over 24 h. Surprisingly, GABAergic transmission onto histaminergic neurons had no effect in regulating the natural sleep-wake cycle and, in the case of GABA(A) receptors, for propofol-induced loss of righting reflex. The latter finding makes it unlikely that the histaminergic TMN has a central role in anesthesia. GABA(B) receptors on histaminergic neurons were dispensable for all behaviors examined. Synaptic inhibition of histaminergic cells by GABA(A) receptors, however, was essential for habituation to a novel environment.
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