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Paveliev M, Egorchev AA, Musin F, Lipachev N, Melnikova A, Gimadutdinov RM, Kashipov AR, Molotkov D, Chickrin DE, Aganov AV. Perineuronal Net Microscopy: From Brain Pathology to Artificial Intelligence. Int J Mol Sci 2024; 25:4227. [PMID: 38673819 PMCID: PMC11049984 DOI: 10.3390/ijms25084227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/31/2024] [Accepted: 04/05/2024] [Indexed: 04/28/2024] Open
Abstract
Perineuronal nets (PNN) are a special highly structured type of extracellular matrix encapsulating synapses on large populations of CNS neurons. PNN undergo structural changes in schizophrenia, epilepsy, Alzheimer's disease, stroke, post-traumatic conditions, and some other brain disorders. The functional role of the PNN microstructure in brain pathologies has remained largely unstudied until recently. Here, we review recent research implicating PNN microstructural changes in schizophrenia and other disorders. We further concentrate on high-resolution studies of the PNN mesh units surrounding synaptic boutons to elucidate fine structural details behind the mutual functional regulation between the ECM and the synaptic terminal. We also review some updates regarding PNN as a potential pharmacological target. Artificial intelligence (AI)-based methods are now arriving as a new tool that may have the potential to grasp the brain's complexity through a wide range of organization levels-from synaptic molecular events to large scale tissue rearrangements and the whole-brain connectome function. This scope matches exactly the complex role of PNN in brain physiology and pathology processes, and the first AI-assisted PNN microscopy studies have been reported. To that end, we report here on a machine learning-assisted tool for PNN mesh contour tracing.
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Affiliation(s)
- Mikhail Paveliev
- Neuroscience Center, University of Helsinki, Haartmaninkatu 8, 00290 Helsinki, Finland
| | - Anton A. Egorchev
- Institute of Computational Mathematics and Information Technologies, Kazan Federal University, Kremlyovskaya 35, Kazan 420008, Tatarstan, Russia; (A.A.E.); (F.M.); (R.M.G.)
| | - Foat Musin
- Institute of Computational Mathematics and Information Technologies, Kazan Federal University, Kremlyovskaya 35, Kazan 420008, Tatarstan, Russia; (A.A.E.); (F.M.); (R.M.G.)
| | - Nikita Lipachev
- Institute of Physics, Kazan Federal University, Kremlyovskaya 16a, Kazan 420008, Tatarstan, Russia; (N.L.); (A.V.A.)
| | - Anastasiia Melnikova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Karl Marx 74, Kazan 420015, Tatarstan, Russia;
| | - Rustem M. Gimadutdinov
- Institute of Computational Mathematics and Information Technologies, Kazan Federal University, Kremlyovskaya 35, Kazan 420008, Tatarstan, Russia; (A.A.E.); (F.M.); (R.M.G.)
| | - Aidar R. Kashipov
- Institute of Artificial Intelligence, Robotics and Systems Engineering, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Tatarstan, Russia; (A.R.K.); (D.E.C.)
| | - Dmitry Molotkov
- Biomedicum Imaging Unit, University of Helsinki, Haartmaninkatu 8, 00014 Helsinki, Finland;
| | - Dmitry E. Chickrin
- Institute of Artificial Intelligence, Robotics and Systems Engineering, Kazan Federal University, Kremlyovskaya 18, Kazan 420008, Tatarstan, Russia; (A.R.K.); (D.E.C.)
| | - Albert V. Aganov
- Institute of Physics, Kazan Federal University, Kremlyovskaya 16a, Kazan 420008, Tatarstan, Russia; (N.L.); (A.V.A.)
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2
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Ozsvár A, Sieburg MC, Sietam MD, Hou WH, Capogna M. A combinatory genetic strategy for targeting neurogliaform neurons in the mouse basolateral amygdala. Front Cell Neurosci 2024; 18:1254460. [PMID: 38362542 PMCID: PMC10867116 DOI: 10.3389/fncel.2024.1254460] [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: 07/07/2023] [Accepted: 01/09/2024] [Indexed: 02/17/2024] Open
Abstract
The mouse basolateral amygdala (BLA) contains various GABAergic interneuron subpopulations, which have distinctive roles in the neuronal microcircuit controlling numerous behavioral functions. In mice, roughly 15% of the BLA GABAergic interneurons express neuropeptide Y (NPY), a reasonably characteristic marker for neurogliaform cells (NGFCs) in cortical-like brain structures. However, genetically labeled putative NPY-expressing interneurons in the BLA yield a mixture of interneuron subtypes besides NGFCs. Thus, selective molecular markers are lacking for genetically accessing NGFCs in the BLA. Here, we validated the NGFC-specific labeling with a molecular marker, neuron-derived neurotrophic factor (NDNF), in the mouse BLA, as such specificity has been demonstrated in the neocortex and hippocampus. We characterized genetically defined NDNF-expressing (NDNF+) GABAergic interneurons in the mouse BLA by combining the Ndnf-IRES2-dgCre-D transgenic mouse line with viral labeling, immunohistochemical staining, and in vitro electrophysiology. We found that BLA NDNF+ GABAergic cells mainly expressed NGFC neurochemical markers NPY and reelin (Reln) and exhibited small round soma and dense axonal arborization. Whole-cell patch clamp recordings indicated that most NDNF+ interneurons showed late spiking and moderate firing adaptation. Moreover, ∼81% of BLA NDNF+ cells generated retroaxonal action potential after current injections or optogenetic stimulations, frequently developing into persistent barrage firing. Optogenetic activation of the BLA NDNF+ cell population yielded both GABAA- and GABAB receptor-mediated currents onto BLA pyramidal neurons (PNs). We demonstrate a combinatory strategy combining the NDNF-cre mouse line with viral transfection to specifically target adult mouse BLA NGFCs and further explore their functional and behavioral roles.
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Affiliation(s)
- Attila Ozsvár
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Meike Claudia Sieburg
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark
| | - Monica Dahlstrup Sietam
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark
| | - Wen-Hsien Hou
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience - DANDRITE, Aarhus University, Aarhus, Denmark
- Center for Proteins in Memory (PROMEMO), Danish National Research Foundation, Aarhus University, Aarhus, Denmark
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3
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Rózsa M, Tóth M, Oláh G, Baka J, Lákovics R, Barzó P, Tamás G. Temporal disparity of action potentials triggered in axon initial segments and distal axons in the neocortex. SCIENCE ADVANCES 2023; 9:eade4511. [PMID: 37824608 PMCID: PMC10569705 DOI: 10.1126/sciadv.ade4511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 04/11/2023] [Indexed: 10/14/2023]
Abstract
Neural population activity determines the timing of synaptic inputs, which arrive to dendrites, cell bodies, and axon initial segments (AISs) of cortical neurons. Action potential initiation in the AIS (AIS-APs) is driven by input integration, and the phase preference of AIS-APs during network oscillations is characteristic to cell classes. Distal regions of cortical axons do not receive synaptic inputs, yet experimental induction protocols can trigger retroaxonal action potentials (RA-APs) in axons distal from the soma. We report spontaneously occurring RA-APs in human and rodent cortical interneurons that appear uncorrelated to inputs and population activity. Network-linked triggering of AIS-APs versus input-independent timing of RA-APs of the same interneurons results in disparate temporal contribution of a single cell to in vivo network operation through perisomatic and distal axonal firing.
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Affiliation(s)
- Márton Rózsa
- ELKH-SZTE Research Group for Cortical Microcircuits, University of Szeged, Szeged, Hungary
| | - Martin Tóth
- ELKH-SZTE Research Group for Cortical Microcircuits, University of Szeged, Szeged, Hungary
| | - Gáspár Oláh
- ELKH-SZTE Research Group for Cortical Microcircuits, University of Szeged, Szeged, Hungary
| | - Judith Baka
- ELKH-SZTE Research Group for Cortical Microcircuits, University of Szeged, Szeged, Hungary
| | - Rajmund Lákovics
- ELKH-SZTE Research Group for Cortical Microcircuits, University of Szeged, Szeged, Hungary
| | - Pál Barzó
- Department of Neurosurgery, University of Szeged, Szeged, Hungary
| | - Gábor Tamás
- ELKH-SZTE Research Group for Cortical Microcircuits, University of Szeged, Szeged, Hungary
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4
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Goldschen-Ohm MP. Benzodiazepine Modulation of GABA A Receptors: A Mechanistic Perspective. Biomolecules 2022; 12:biom12121784. [PMID: 36551212 PMCID: PMC9775625 DOI: 10.3390/biom12121784] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/23/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
Benzodiazepines (BZDs) are a class of widely prescribed psychotropic drugs that target GABAA receptors (GABAARs) to tune inhibitory synaptic signaling throughout the central nervous system. Despite knowing their molecular target for over 40 years, we still do not fully understand the mechanism of modulation at the level of the channel protein. Nonetheless, functional studies, together with recent cryo-EM structures of GABAA(α1)2(βX)2(γ2)1 receptors in complex with BZDs, provide a wealth of information to aid in addressing this gap in knowledge. Here, mechanistic interpretations of functional and structural evidence for the action of BZDs at GABAA(α1)2(βX)2(γ2)1 receptors are reviewed. The goal is not to describe each of the many studies that are relevant to this discussion nor to dissect in detail all the effects of individual mutations or perturbations but rather to highlight general mechanistic principles in the context of recent structural information.
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5
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Suzuki N, Tantirigama MLS, Aung KP, Huang HHY, Bekkers JM. Fast and slow feedforward inhibitory circuits for cortical odor processing. eLife 2022; 11:73406. [PMID: 35297763 PMCID: PMC8929928 DOI: 10.7554/elife.73406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 02/23/2022] [Indexed: 11/23/2022] Open
Abstract
Feedforward inhibitory circuits are key contributors to the complex interplay between excitation and inhibition in the brain. Little is known about the function of feedforward inhibition in the primary olfactory (piriform) cortex. Using in vivo two-photon-targeted patch clamping and calcium imaging in mice, we find that odors evoke strong excitation in two classes of interneurons – neurogliaform (NG) cells and horizontal (HZ) cells – that provide feedforward inhibition in layer 1 of the piriform cortex. NG cells fire much earlier than HZ cells following odor onset, a difference that can be attributed to the faster odor-driven excitatory synaptic drive that NG cells receive from the olfactory bulb. As a result, NG cells strongly but transiently inhibit odor-evoked excitation in layer 2 principal cells, whereas HZ cells provide more diffuse and prolonged feedforward inhibition. Our findings reveal unexpected complexity in the operation of inhibition in the piriform cortex.
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Affiliation(s)
- Norimitsu Suzuki
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Malinda L S Tantirigama
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, Australia.,Neurocure Center for Excellence, Charité Universitätsmedizin Berlin and Humboldt Universität, Berlin, Germany
| | - K Phyu Aung
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Helena H Y Huang
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - John M Bekkers
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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6
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The Case for Clinical Trials with Novel GABAergic Drugs in Diabetes Mellitus and Obesity. Life (Basel) 2022; 12:life12020322. [PMID: 35207609 PMCID: PMC8876029 DOI: 10.3390/life12020322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 11/17/2022] Open
Abstract
Obesity and diabetes mellitus have become the surprising menaces of relative economic well-being worldwide. Gamma amino butyric acid (GABA) has a prominent role in the control of blood glucose, energy homeostasis as well as food intake at several levels of regulation. The effects of GABA in the body are exerted through ionotropic GABAA and metabotropic GABAB receptors. This treatise will focus on the pharmacologic targeting of GABAA receptors to reap beneficial therapeutic effects in diabetes mellitus and obesity. A new crop of drugs selectively targeting GABAA receptors has been under investigation for efficacy in stroke recovery and cognitive deficits associated with schizophrenia. Although these trials have produced mixed outcomes the compounds are safe to use in humans. Preclinical evidence is summarized here to support the rationale of testing some of these compounds in diabetic patients receiving insulin in order to achieve better control of blood glucose levels and to combat the decline of cognitive performance. Potential therapeutic benefits could be achieved (i) By resetting the hypoglycemic counter-regulatory response; (ii) Through trophic actions on pancreatic islets, (iii) By the mobilization of antioxidant defence mechanisms in the brain. Furthermore, preclinical proof-of-concept work, as well as clinical trials that apply the novel GABAA compounds in eating disorders, e.g., olanzapine-induced weight-gain, also appear warranted.
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7
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Figueroa AG, Benkwitz C, Surges G, Kunz N, Homanics GE, Pearce RA. Hippocampal β2-GABA A receptors mediate LTP suppression by etomidate and contribute to long-lasting feedback but not feedforward inhibition of pyramidal neurons. J Neurophysiol 2021; 126:1090-1100. [PMID: 34406874 PMCID: PMC8560413 DOI: 10.1152/jn.00303.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The general anesthetic etomidate, which acts through γ-aminobutyric acid type A (GABAA) receptors, impairs the formation of new memories under anesthesia. This study addresses the molecular and cellular mechanisms by which this occurs. Here, using a new line of genetically engineered mice carrying the GABAA receptor (GABAAR) β2-N265M mutation, we tested the roles of receptors that incorporate GABAA receptor β2 versus β3 subunits to suppression of long-term potentiation (LTP), a cellular model of learning and memory. We found that brain slices from β2-N265M mice resisted etomidate suppression of LTP, indicating that the β2-GABAARs are an essential target in this model. As these receptors are most heavily expressed by interneurons in the hippocampus, this finding supports a role for interneuron modulation in etomidate control of synaptic plasticity. Nevertheless, β2 subunits are also expressed by pyramidal neurons, so they might also contribute. Therefore, using a previously established line of β3-N265M mice, we also examined the contributions of β2- versus β3-GABAARs to GABAA,slow dendritic inhibition, because dendritic inhibition is particularly well suited to controlling synaptic plasticity. We also examined their roles in long-lasting suppression of population activity through feedforward and feedback inhibition. We found that both β2- and β3-GABAARs contribute to GABAA,slow inhibition and that both β2- and β3-GABAARs contribute to feedback inhibition, whereas only β3-GABAARs contribute to feedforward inhibition. We conclude that modulation of β2-GABAARs is essential to etomidate suppression of LTP. Furthermore, to the extent that this occurs through GABAARs on pyramidal neurons, it is through modulation of feedback inhibition.NEW & NOTEWORTHY Etomidate exerts its anesthetic actions through GABAA receptors. However, the mechanism remains unknown. Here, using a hippocampal brain slice model, we show that β2-GABAARs are essential to this effect. We also show that these receptors contribute to long-lasting dendritic inhibition in feedback but not feedforward inhibition of pyramidal neurons. These findings hold implications for understanding how anesthetics block memory formation and, more generally, how inhibitory circuits control learning and memory.
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Affiliation(s)
- Alexander G Figueroa
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Claudia Benkwitz
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin.,Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gabe Surges
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Nicholas Kunz
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Gregg E Homanics
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert A Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, Wisconsin
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8
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Ozsvár A, Komlósi G, Oláh G, Baka J, Molnár G, Tamás G. Predominantly linear summation of metabotropic postsynaptic potentials follows coactivation of neurogliaform interneurons. eLife 2021; 10:65634. [PMID: 34308838 PMCID: PMC8360660 DOI: 10.7554/elife.65634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 07/14/2021] [Indexed: 01/13/2023] Open
Abstract
Summation of ionotropic receptor-mediated responses is critical in neuronal computation by shaping input-output characteristics of neurons. However, arithmetics of summation for metabotropic signals are not known. We characterized the combined ionotropic and metabotropic output of neocortical neurogliaform cells (NGFCs) using electrophysiological and anatomical methods in the rat cerebral cortex. These experiments revealed that GABA receptors are activated outside release sites and confirmed coactivation of putative NGFCs in superficial cortical layers in vivo. Triple recordings from presynaptic NGFCs converging to a postsynaptic neuron revealed sublinear summation of ionotropic GABAA responses and linear summation of metabotropic GABAB responses. Based on a model combining properties of volume transmission and distributions of all NGFC axon terminals, we predict that in 83% of cases one or two NGFCs can provide input to a point in the neuropil. We suggest that interactions of metabotropic GABAergic responses remain linear even if most superficial layer interneurons specialized to recruit GABAB receptors are simultaneously active.
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Affiliation(s)
- Attila Ozsvár
- MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Gergely Komlósi
- MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Gáspár Oláh
- MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Judith Baka
- MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Gábor Molnár
- MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Gábor Tamás
- MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
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9
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Castellano D, Shepard RD, Lu W. Looking for Novelty in an "Old" Receptor: Recent Advances Toward Our Understanding of GABA ARs and Their Implications in Receptor Pharmacology. Front Neurosci 2021; 14:616298. [PMID: 33519367 PMCID: PMC7841293 DOI: 10.3389/fnins.2020.616298] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 12/14/2020] [Indexed: 12/16/2022] Open
Abstract
Diverse populations of GABAA receptors (GABAARs) throughout the brain mediate fast inhibitory transmission and are modulated by various endogenous ligands and therapeutic drugs. Deficits in GABAAR signaling underlie the pathophysiology behind neurological and neuropsychiatric disorders such as epilepsy, anxiety, and depression. Pharmacological intervention for these disorders relies on several drug classes that target GABAARs, such as benzodiazepines and more recently neurosteroids. It has been widely demonstrated that subunit composition and receptor stoichiometry impact the biophysical and pharmacological properties of GABAARs. However, current GABAAR-targeting drugs have limited subunit selectivity and produce their therapeutic effects concomitantly with undesired side effects. Therefore, there is still a need to develop more selective GABAAR pharmaceuticals, as well as evaluate the potential for developing next-generation drugs that can target accessory proteins associated with native GABAARs. In this review, we briefly discuss the effects of benzodiazepines and neurosteroids on GABAARs, their use as therapeutics, and some of the pitfalls associated with their adverse side effects. We also discuss recent advances toward understanding the structure, function, and pharmacology of GABAARs with a focus on benzodiazepines and neurosteroids, as well as newly identified transmembrane proteins that modulate GABAARs.
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Affiliation(s)
- David Castellano
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Ryan David Shepard
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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10
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Comprehensive Estimates of Potential Synaptic Connections in Local Circuits of the Rodent Hippocampal Formation by Axonal-Dendritic Overlap. J Neurosci 2020; 41:1665-1683. [PMID: 33361464 DOI: 10.1523/jneurosci.1193-20.2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 10/19/2020] [Accepted: 12/13/2020] [Indexed: 12/12/2022] Open
Abstract
A quantitative description of the hippocampal formation synaptic architecture is essential for understanding the neural mechanisms of episodic memory. Yet the existing knowledge of connectivity statistics between different neuron types in the rodent hippocampus only captures a mere 5% of this circuitry. We present a systematic pipeline to produce first-approximation estimates for most of the missing information. Leveraging the www.Hippocampome.org knowledge base, we derive local connection parameters between distinct pairs of morphologically identified neuron types based on their axonal-dendritic overlap within every layer and subregion of the hippocampal formation. Specifically, we adapt modern image analysis technology to determine the parcel-specific neurite lengths of every neuron type from representative morphologic reconstructions obtained from either sex. We then compute the average number of synapses per neuron pair using relevant anatomic volumes from the mouse brain atlas and ultrastructurally established interaction distances. Hence, we estimate connection probabilities and number of contacts for >1900 neuron type pairs, increasing the available quantitative assessments more than 11-fold. Connectivity statistics thus remain unknown for only a minority of potential synapses in the hippocampal formation, including those involving long-range (23%) or perisomatic (6%) connections and neuron types without morphologic tracings (7%). The described approach also yields approximate measurements of synaptic distances from the soma along the dendritic and axonal paths, which may affect signal attenuation and delay. Overall, this dataset fills a substantial gap in quantitatively describing hippocampal circuits and provides useful model specifications for biologically realistic neural network simulations, until further direct experimental data become available.SIGNIFICANCE STATEMENT The hippocampal formation is a crucial functional substrate for episodic memory and spatial representation. Characterizing the complex neuron type circuit of this brain region is thus important to understand the cellular mechanisms of learning and navigation. Here we present the first numerical estimates of connection probabilities, numbers of contacts per connected pair, and synaptic distances from the soma along the axonal and dendritic paths, for more than 1900 distinct neuron type pairs throughout the dentate gyrus, CA3, CA2, CA1, subiculum, and entorhinal cortex. This comprehensive dataset, publicly released online at www.Hippocampome.org, constitutes an unprecedented quantification of the majority of the local synaptic circuit for a prominent mammalian neural system and provides an essential foundation for data-driven, anatomically realistic neural network models.
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11
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Gesuita L, Karayannis T. A 'Marginal' tale: the development of the neocortical layer 1. Curr Opin Neurobiol 2020; 66:37-47. [PMID: 33069991 DOI: 10.1016/j.conb.2020.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/03/2020] [Accepted: 09/02/2020] [Indexed: 01/06/2023]
Abstract
The development of neocortical layer 1 is a very dynamic process and the scene of multiple transient events, with Cajal-Retzius cell death being one of the most characteristic ones. Layer 1 is also the route of migration for a substantial number of GABAergic interneurons during embryogenesis and where some of which will ultimately remain in the adult. The two cell types, together with a diverse set of incoming axons and dendrites, create an early circuit that will dramatically change in structure and function in the adult cortex to give prominence to inhibition. Through the engagement of a diverse set of GABAergic inhibitory cells by bottom-up and top-down inputs, adult layer 1 becomes a powerful computational platform for the neocortex.
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Affiliation(s)
- Lorenzo Gesuita
- Laboratory of Neural Circuit Assembly, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Theofanis Karayannis
- Laboratory of Neural Circuit Assembly, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland.
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12
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Capogna M, Castillo PE, Maffei A. The ins and outs of inhibitory synaptic plasticity: Neuron types, molecular mechanisms and functional roles. Eur J Neurosci 2020; 54:6882-6901. [PMID: 32663353 DOI: 10.1111/ejn.14907] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/30/2020] [Accepted: 07/08/2020] [Indexed: 01/05/2023]
Abstract
GABAergic interneurons are highly diverse, and their synaptic outputs express various forms of plasticity. Compelling evidence indicates that activity-dependent changes of inhibitory synaptic transmission play a significant role in regulating neural circuits critically involved in learning and memory and circuit refinement. Here, we provide an updated overview of inhibitory synaptic plasticity with a focus on the hippocampus and neocortex. To illustrate the diversity of inhibitory interneurons, we discuss the case of two highly divergent interneuron types, parvalbumin-expressing basket cells and neurogliaform cells, which support unique roles on circuit dynamics. We also present recent progress on the molecular mechanisms underlying long-term, activity-dependent plasticity of fast inhibitory transmission. Lastly, we discuss the role of inhibitory synaptic plasticity in neuronal circuits' function. The emerging picture is that inhibitory synaptic transmission in the CNS is extremely diverse, undergoes various mechanistically distinct forms of plasticity and contributes to a much more refined computational role than initially thought. Both the remarkable diversity of inhibitory interneurons and the various forms of plasticity expressed by GABAergic synapses provide an amazingly rich inhibitory repertoire that is central to a variety of complex neural circuit functions, including memory.
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Affiliation(s)
- Marco Capogna
- Department of Biomedicine, Danish National Research Foundation Center of Excellence PROMEMO, Aarhus University, Aarhus, Denmark
| | - Pablo E Castillo
- Dominck P Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA.,Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Arianna Maffei
- Center for Neural Circuit Dynamics and Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
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13
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Vaden RJ, Gonzalez JC, Tsai MC, Niver AJ, Fusilier AR, Griffith CM, Kramer RH, Wadiche JI, Overstreet-Wadiche L. Parvalbumin interneurons provide spillover to newborn and mature dentate granule cells. eLife 2020; 9:54125. [PMID: 32602839 PMCID: PMC7326496 DOI: 10.7554/elife.54125] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/19/2020] [Indexed: 01/09/2023] Open
Abstract
Parvalbumin-expressing interneurons (PVs) in the dentate gyrus provide activity-dependent regulation of adult neurogenesis as well as maintain inhibitory control of mature neurons. In mature neurons, PVs evoke GABAA postsynaptic currents (GPSCs) with fast rise and decay phases that allow precise control of spike timing, yet synaptic currents with fast kinetics do not appear in adult-born neurons until several weeks after cell birth. Here we used mouse hippocampal slices to address how PVs signal to newborn neurons prior to the appearance of fast GPSCs. Whereas PV-evoked currents in mature neurons exhibit hallmark fast rise and decay phases, newborn neurons display slow GPSCs with characteristics of spillover signaling. We also unmasked slow spillover currents in mature neurons in the absence of fast GPSCs. Our results suggest that PVs mediate slow spillover signaling in addition to conventional fast synaptic signaling, and that spillover transmission mediates activity-dependent regulation of early events in adult neurogenesis.
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Affiliation(s)
- Ryan J Vaden
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Jose Carlos Gonzalez
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Ming-Chi Tsai
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, United States
| | - Anastasia J Niver
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Allison R Fusilier
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Chelsea M Griffith
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | - Richard H Kramer
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, United States
| | - Jacques I Wadiche
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
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14
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Ecker A, Romani A, Sáray S, Káli S, Migliore M, Falck J, Lange S, Mercer A, Thomson AM, Muller E, Reimann MW, Ramaswamy S. Data-driven integration of hippocampal CA1 synaptic physiology in silico. Hippocampus 2020; 30:1129-1145. [PMID: 32520422 PMCID: PMC7687201 DOI: 10.1002/hipo.23220] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 04/20/2020] [Accepted: 05/07/2020] [Indexed: 12/31/2022]
Abstract
The anatomy and physiology of monosynaptic connections in rodent hippocampal CA1 have been extensively studied in recent decades. Yet, the resulting knowledge remains disparate and difficult to reconcile. Here, we present a data‐driven approach to integrate the current state‐of‐the‐art knowledge on the synaptic anatomy and physiology of rodent hippocampal CA1, including axo‐dendritic innervation patterns, number of synapses per connection, quantal conductances, neurotransmitter release probability, and short‐term plasticity into a single coherent resource. First, we undertook an extensive literature review of paired recordings of hippocampal neurons and compiled experimental data on their synaptic anatomy and physiology. The data collected in this manner is sparse and inhomogeneous due to the diversity of experimental techniques used by different groups, which necessitates the need for an integrative framework to unify these data. To this end, we extended a previously developed workflow for the neocortex to constrain a unifying in silico reconstruction of the synaptic physiology of CA1 connections. Our work identifies gaps in the existing knowledge and provides a complementary resource toward a more complete quantification of synaptic anatomy and physiology in the rodent hippocampal CA1 region.
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Affiliation(s)
- András Ecker
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Armando Romani
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Sára Sáray
- Institute of Experimental Medicine, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Szabolcs Káli
- Institute of Experimental Medicine, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Joanne Falck
- UCL School of Pharmacy, University College London, London, UK
| | - Sigrun Lange
- UCL School of Pharmacy, University College London, London, UK.,School of Life Sciences, University of Westminster, London, UK
| | - Audrey Mercer
- UCL School of Pharmacy, University College London, London, UK
| | - Alex M Thomson
- UCL School of Pharmacy, University College London, London, UK
| | - Eilif Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Michael W Reimann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Srikanth Ramaswamy
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
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15
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Szegedi V, Paizs M, Baka J, Barzó P, Molnár G, Tamas G, Lamsa K. Robust perisomatic GABAergic self-innervation inhibits basket cells in the human and mouse supragranular neocortex. eLife 2020; 9:51691. [PMID: 31916939 PMCID: PMC6984819 DOI: 10.7554/elife.51691] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/08/2020] [Indexed: 01/08/2023] Open
Abstract
Inhibitory autapses are self-innervating synaptic connections in GABAergic interneurons in the brain. Autapses in neocortical layers have not been systematically investigated, and their function in different mammalian species and specific interneuron types is poorly known. We investigated GABAergic parvalbumin-expressing basket cells (pvBCs) in layer 2/3 (L2/3) in human neocortical tissue resected in deep-brain surgery, and in mice as control. Most pvBCs showed robust GABAAR-mediated self-innervation in both species, but autapses were rare in nonfast-spiking GABAergic interneurons. Light- and electron microscopy analyses revealed pvBC axons innervating their own soma and proximal dendrites. GABAergic self-inhibition conductance was similar in human and mouse pvBCs and comparable to that of synapses from pvBCs to other L2/3 neurons. Autaptic conductance prolonged somatic inhibition in pvBCs after a spike and inhibited repetitive firing. Perisomatic autaptic inhibition is common in both human and mouse pvBCs of supragranular neocortex, where they efficiently control discharge of the pvBCs.
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Affiliation(s)
- Viktor Szegedi
- MTA-NAP Research Group for Inhibitory Interneurons and Plasticity, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Melinda Paizs
- MTA-NAP Research Group for Inhibitory Interneurons and Plasticity, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Judith Baka
- MTA-SZTE Research Group for Cortical Microcircuits, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Pál Barzó
- Department of Neurosurgery, University of Szeged, Szeged, Hungary
| | - Gábor Molnár
- MTA-SZTE Research Group for Cortical Microcircuits, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Gabor Tamas
- MTA-SZTE Research Group for Cortical Microcircuits, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Karri Lamsa
- MTA-NAP Research Group for Inhibitory Interneurons and Plasticity, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
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16
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Yamamoto R, Furuyama T, Sugai T, Ono M, Pare D, Kato N. Serotonergic control of GABAergic inhibition in the lateral amygdala. J Neurophysiol 2019; 123:670-681. [PMID: 31875487 DOI: 10.1152/jn.00500.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Much evidence implicates the serotonergic regulation of the amygdala in anxiety. Thus the present study was undertaken to characterize the influence of serotonin (5-HT) on principal neurons (PNs) of the rat lateral amygdala (LA), using whole cell recordings in vitro. Because inhibition is a major determinant of PN activity, we focused on the control of GABAergic transmission by 5-HT. IPSCs were elicited by local electrical stimulation of LA in the presence of glutamate receptor antagonists. We found that 5-HT reduces GABAA inhibitory postsynaptic currents (IPSCs) via presynaptic 5-HT1B receptors. While the presynaptic inhibition of GABA release also attenuated GABAB currents, this effect was less pronounced than for GABAA currents because 5-HT also induced a competing postsynaptic enhancement of GABAB currents. That is, GABAB currents elicited by pressure application of GABA or baclofen were enhanced by 5-HT. In addition, we obtained evidence suggesting that 5-HT differentially regulates distinct subsets of GABAergic synapses. Indeed, GABAA IPSCs were comprised of two components: a relatively 5-HT-insensitive IPSC that had a fast time course and a 5-HT-sensitive component that had a slower time course. Because the relative contribution of these two components varied depending on whether neurons were recorded at proximity versus at a distance from the stimulating electrodes, we speculate that distinct subtypes of local-circuit cells contribute the two contingents of GABAergic synapses. Overall, our results indicate that 5-HT is a potent regulator of synaptic inhibition in LA.NEW & NOTEWORTHY We report that 5-HT, acting via presynaptic 5-HT1B receptors, attenuates GABAA IPSCs by reducing GABA release in the lateral amygdala (LA). In parallel, 5-HT enhances GABAB currents postsynaptically, such that GABAB inhibitory postsynaptic currents (IPSCs) are relatively preserved from the presynaptic inhibition of GABA release. We also found that the time course of 5-HT-sensitive and -insensitive GABAA IPSCs differ. Together, these results indicate that 5-HT is a potent regulator of synaptic inhibition in LA.
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Affiliation(s)
- Ryo Yamamoto
- Department of Physiology, Kanazawa Medical University, Ishikawa, Japan
| | - Takafumi Furuyama
- Department of Physiology, Kanazawa Medical University, Ishikawa, Japan
| | - Tokio Sugai
- Department of Physiology, Kanazawa Medical University, Ishikawa, Japan
| | - Munenori Ono
- Department of Physiology, Kanazawa Medical University, Ishikawa, Japan
| | - Denis Pare
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, New Jersey
| | - Nobuo Kato
- Department of Physiology, Kanazawa Medical University, Ishikawa, Japan
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17
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Enhanced Dendritic Inhibition and Impaired NMDAR Activation in a Mouse Model of Down Syndrome. J Neurosci 2019; 39:5210-5221. [PMID: 31000585 DOI: 10.1523/jneurosci.2723-18.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 11/21/2022] Open
Abstract
Down syndrome (DS) or Trisomy 21 is a developmental disorder leading to cognitive deficits, including disruption of hippocampus-dependent learning and memory. Enhanced inhibition has been suggested to underlie these deficits in DS based on studies using the Ts65Dn mouse model. Here we show that, in this mouse model, GABAergic synaptic inhibition onto dendrites of hippocampal pyramidal cells is increased. By contrast, somatic inhibition was not altered. In addition, synaptic NMDAR currents were reduced. Furthermore, dendritic inhibition was mediated via nonlinear α5-subunit containing GABAARs that closely matched the kinetics and voltage dependence of NMDARs. Thus, enhanced dendritic inhibition and reduced NMDA currents strongly decreased burst-induced NMDAR-mediated depolarization and impaired LTP induction. Finally, selective reduction of α5-GABAAR-mediated inhibition rescued both burst-induced synaptic NMDAR activation and synaptic plasticity. These results demonstrate that reduced synaptic NMDAR activation and synaptic plasticity in the Ts65Dn mouse model of DS can be corrected by specifically targeting nonlinear dendritic inhibition.SIGNIFICANCE STATEMENT Mild to moderate intellectual disability is a prominent feature of Down syndrome. Previous studies in mouse models suggest that increased synaptic inhibition is a main factor for decreased synaptic plasticity, the cellular phenomenon underlying memory. The present study shows that increased inhibition specifically onto dendrites together with reduced NMDAR content in excitatory synapses may be the cause. Reducing a slow nonlinear component that is specific to dendritic inhibitory inputs and mediated by α5 subunit-containing GABAA receptors rescues both NMDAR activation and synaptic plasticity.
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18
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Tepper JM, Koós T, Ibanez-Sandoval O, Tecuapetla F, Faust TW, Assous M. Heterogeneity and Diversity of Striatal GABAergic Interneurons: Update 2018. Front Neuroanat 2018; 12:91. [PMID: 30467465 PMCID: PMC6235948 DOI: 10.3389/fnana.2018.00091] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022] Open
Abstract
Our original review, “Heterogeneity and Diversity of Striatal GABAergic Interneurons,” to which this is an invited update, was published in December, 2010 in Frontiers is Neuroanatomy. In that article, we reviewed several decades’ worth of anatomical and electrophysiological data on striatal parvalbumin (PV)-, neuropeptide Y (NPY)- and calretinin(CR)-expressing GABAergic interneurons from many laboratories including our own. In addition, we reported on a recently discovered novel tyrosine hydroxylase (TH) expressing GABAergic interneuron class first revealed in transgenic TH EGFP reporter mouse line. In this review, we report on further advances in the understanding of the functional properties of previously reported striatal GABAergic interneurons and their synaptic connections. With the application of new transgenic fluorescent reporter and Cre-driver/reporter lines, plus optogenetic, chemogenetic and viral transduction methods, several additional subtypes of novel striatal GABAergic interneurons have been discovered, as well as the synaptic networks in which they are embedded. These findings make it clear that previous hypotheses in which striatal GABAergic interneurons modulate and/or control the firing of spiny neurons principally by simple feedforward and/or feedback inhibition are at best incomplete. A more accurate picture is one in which there are highly selective and specific afferent inputs, synaptic connections between different interneuron subtypes and spiny neurons and among different GABAergic interneurons that result in the formation of functional networks and ensembles of spiny neurons.
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Affiliation(s)
- James M Tepper
- Center For Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, United States
| | - Tibor Koós
- Center For Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, United States
| | - Osvaldo Ibanez-Sandoval
- Center For Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, United States
| | - Fatuel Tecuapetla
- Center For Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, United States
| | - Thomas W Faust
- Center For Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, United States
| | - Maxime Assous
- Center For Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ, United States
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19
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Booker SA, Vida I. Morphological diversity and connectivity of hippocampal interneurons. Cell Tissue Res 2018; 373:619-641. [PMID: 30084021 PMCID: PMC6132631 DOI: 10.1007/s00441-018-2882-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/03/2018] [Indexed: 12/21/2022]
Abstract
The mammalian forebrain is constructed from ensembles of neurons that form local microcircuits giving rise to the exquisite cognitive tasks the mammalian brain can perform. Hippocampal neuronal circuits comprise populations of relatively homogenous excitatory neurons, principal cells and exceedingly heterogeneous inhibitory neurons, the interneurons. Interneurons release GABA from their axon terminals and are capable of controlling excitability in every cellular compartment of principal cells and interneurons alike; thus, they provide a brake on excess activity, control the timing of neuronal discharge and provide modulation of synaptic transmission. The dendritic and axonal morphology of interneurons, as well as their afferent and efferent connections within hippocampal circuits, is central to their ability to differentially control excitability, in a cell-type- and compartment-specific manner. This review aims to provide an up-to-date compendium of described hippocampal interneuron subtypes, with respect to their morphology, connectivity, neurochemistry and physiology, a full understanding of which will in time help to explain the rich diversity of neuronal function.
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Affiliation(s)
- Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK.
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité - Universitätmedizin Berlin, Berlin, Germany.
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20
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Anstötz M, Quattrocolo G, Maccaferri G. Cajal-Retzius cells and GABAergic interneurons of the developing hippocampus: Close electrophysiological encounters of the third kind. Brain Res 2018; 1697:124-133. [PMID: 30071194 DOI: 10.1016/j.brainres.2018.07.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/17/2018] [Accepted: 07/28/2018] [Indexed: 01/24/2023]
Abstract
In contrast to the large number of studies investigating the electrophysiological properties and synaptic connectivity of hippocampal pyramidal neurons, granule cells, and GABAergic interneurons, much less is known about Cajal-Retzius cells. In this review article, we discuss the possible reasons underlying this difference, and review experimental work performed on this cell type in the hippocampus, comparing it with results obtained in the neocortex. Our main emphasis is on data obtained with in vitro electrophysiology. In particular, we address the bidirectional connectivity between Cajal-Retzius cells and GABAergic interneurons, examine their synaptic properties and propose specific functions of Cajal-Retzius cell/GABAergic interneuron microcircuits. Lastly, we discuss the potential involvement of these microcircuits in critical physiological hippocampal functions such as postnatal neurogenesis or pathological scenarios such as temporal lobe epilepsy.
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Affiliation(s)
- Max Anstötz
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Giulia Quattrocolo
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gianmaria Maccaferri
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.
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21
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An Essential Role for the Tetraspanin LHFPL4 in the Cell-Type-Specific Targeting and Clustering of Synaptic GABA A Receptors. Cell Rep 2018; 21:70-83. [PMID: 28978485 PMCID: PMC5640807 DOI: 10.1016/j.celrep.2017.09.025] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/17/2017] [Accepted: 09/06/2017] [Indexed: 02/04/2023] Open
Abstract
Inhibitory synaptic transmission requires the targeting and stabilization of GABAA receptors (GABAARs) at synapses. The mechanisms responsible remain poorly understood, and roles for transmembrane accessory proteins have not been established. Using molecular, imaging, and electrophysiological approaches, we identify the tetraspanin LHFPL4 as a critical regulator of postsynaptic GABAAR clustering in hippocampal pyramidal neurons. LHFPL4 interacts tightly with GABAAR subunits and is selectively enriched at inhibitory synapses. In LHFPL4 knockout mice, there is a dramatic cell-type-specific reduction in GABAAR and gephyrin clusters and an accumulation of large intracellular gephyrin aggregates in vivo. While GABAARs are still trafficked to the neuronal surface in pyramidal neurons, they are no longer localized at synapses, resulting in a profound loss of fast inhibitory postsynaptic currents. Hippocampal interneuron currents remain unaffected. Our results establish LHFPL4 as a synapse-specific tetraspanin essential for inhibitory synapse function and provide fresh insights into the molecular make-up of inhibitory synapses. LHFPL4 is a tetraspanin enriched at inhibitory synapses that complexes with GABAARs LHFPL4 is important for GABAAR clustering both in vitro and in vivo LHFPL4 is required for the surface clustering but not the trafficking of GABAARs GABAergic synaptic inputs on CA1 pyramidal neurons, but not interneurons, require LHFPL4
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22
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Kang YJ, Lewis HES, Young MW, Govindaiah G, Greenfield LJ, Garcia-Rill E, Lee SH. Cell Type-specific Intrinsic Perithreshold Oscillations in Hippocampal GABAergic Interneurons. Neuroscience 2018; 376:80-93. [PMID: 29462702 PMCID: PMC5978001 DOI: 10.1016/j.neuroscience.2018.02.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 02/08/2018] [Accepted: 02/09/2018] [Indexed: 01/01/2023]
Abstract
The hippocampus plays a critical role in learning, memory, and spatial processing through coordinated network activity including theta and gamma oscillations. Recent evidence suggests that hippocampal subregions (e.g., CA1) can generate these oscillations at the network level, at least in part, through GABAergic interneurons. However, it is unclear whether specific GABAergic interneurons generate intrinsic theta and/or gamma oscillations at the single-cell level. Since major types of CA1 interneurons (i.e., parvalbumin-positive basket cells (PVBCs), cannabinoid type 1 receptor-positive basket cells (CB1BCs), Schaffer collateral-associated cells (SCAs), neurogliaform cells and ivy cells) are thought to play key roles in network theta and gamma oscillations in the hippocampus, we tested the hypothesis that these cells generate intrinsic perithreshold oscillations at the single-cell level. We performed whole-cell patch-clamp recordings from GABAergic interneurons in the CA1 region of the mouse hippocampus in the presence of synaptic blockers to identify intrinsic perithreshold membrane potential oscillations. The majority of PVBCs (83%), but not the other interneuron subtypes, produced intrinsic perithreshold gamma oscillations if the membrane potential remained above -45 mV. In contrast, CB1BCs, SCAs, neurogliaform cells, ivy cells, and the remaining PVBCs (17%) produced intrinsic theta, but not gamma, oscillations. These oscillations were prevented by blockers of persistent sodium current. These data demonstrate that the major types of hippocampal interneurons produce distinct frequency bands of intrinsic perithreshold membrane oscillations.
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Affiliation(s)
- Young-Jin Kang
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | | | - Mason William Young
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Gubbi Govindaiah
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Lazar John Greenfield
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA; Department of Neurology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Edgar Garcia-Rill
- Center for Translational Neuroscience, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Sang-Hun Lee
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA; Center for Translational Neuroscience, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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23
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Pálvölgyi A, Móricz K, Pataki Á, Mihalik B, Gigler G, Megyeri K, Udvari S, Gacsályi I, Antoni FA. Loop F of the GABA A receptor alpha subunit governs GABA potency. Neuropharmacology 2018; 128:408-415. [DOI: 10.1016/j.neuropharm.2017.10.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/29/2017] [Accepted: 10/31/2017] [Indexed: 12/28/2022]
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24
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Pelkey KA, Chittajallu R, Craig MT, Tricoire L, Wester JC, McBain CJ. Hippocampal GABAergic Inhibitory Interneurons. Physiol Rev 2017; 97:1619-1747. [PMID: 28954853 DOI: 10.1152/physrev.00007.2017] [Citation(s) in RCA: 490] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/16/2017] [Accepted: 05/26/2017] [Indexed: 12/11/2022] Open
Abstract
In the hippocampus GABAergic local circuit inhibitory interneurons represent only ~10-15% of the total neuronal population; however, their remarkable anatomical and physiological diversity allows them to regulate virtually all aspects of cellular and circuit function. Here we provide an overview of the current state of the field of interneuron research, focusing largely on the hippocampus. We discuss recent advances related to the various cell types, including their development and maturation, expression of subtype-specific voltage- and ligand-gated channels, and their roles in network oscillations. We also discuss recent technological advances and approaches that have permitted high-resolution, subtype-specific examination of their roles in numerous neural circuit disorders and the emerging therapeutic strategies to ameliorate such pathophysiological conditions. The ultimate goal of this review is not only to provide a touchstone for the current state of the field, but to help pave the way for future research by highlighting where gaps in our knowledge exist and how a complete appreciation of their roles will aid in future therapeutic strategies.
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Affiliation(s)
- Kenneth A Pelkey
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Ramesh Chittajallu
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Michael T Craig
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Ludovic Tricoire
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Jason C Wester
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Chris J McBain
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
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25
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Etherington LA, Mihalik B, Pálvölgyi A, Ling I, Pallagi K, Kertész S, Varga P, Gunn BG, Brown AR, Livesey MR, Monteiro O, Belelli D, Barkóczy J, Spedding M, Gacsályi I, Antoni FA, Lambert JJ. Selective inhibition of extra-synaptic α5-GABA A receptors by S44819, a new therapeutic agent. Neuropharmacology 2017; 125:353-364. [PMID: 28807671 DOI: 10.1016/j.neuropharm.2017.08.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/07/2017] [Accepted: 08/09/2017] [Indexed: 01/18/2023]
Abstract
In the mammalian central nervous system (CNS) GABAA receptors (GABAARs) mediate neuronal inhibition and are important therapeutic targets. GABAARs are composed of 5 subunits, drawn from 19 proteins, underpinning expression of 20-30 GABAAR subtypes. In the CNS these isoforms are heterogeneously expressed and exhibit distinct physiological and pharmacological properties. We report the discovery of S44819, a novel tricyclic oxazolo-2,3-benzodiazepine-derivative, that selectively inhibits α5-subunit-containing GABAARs (α5-GABAARs). Current α5-GABAAR inhibitors bind to the "benzodiazepine site". However, in HEK293 cells expressing recombinant α5-GABAARs, S44819 had no effect on 3H-flumazenil binding, but displaced the GABAAR agonist 3H-muscimol and competitively inhibited the GABA-induced responses. Importantly, we reveal that the α5-subunit selectivity is uniquely governed by amino acid residues within the α-subunit F-loop, a region associated with GABA binding. In mouse hippocampal CA1 neurons, S44819 enhanced long-term potentiation (LTP), blocked a tonic current mediated by extrasynaptic α5-GABAARs, but had no effect on synaptic GABAARs. In mouse thalamic neurons, S44819 had no effect on the tonic current mediated by δ-GABAARs, or on synaptic (α1β2γ2) GABAARs. In rats, S44819 enhanced object recognition memory and reversed scopolamine-induced impairment of working memory in the eight-arm radial maze. In conclusion, S44819 is a first in class compound that uniquely acts as a potent, competitive, selective antagonist of recombinant and native α5-GABAARs. Consequently, S44819 enhances hippocampal synaptic plasticity and exhibits pro-cognitive efficacy. Given this profile, S44819 may improve cognitive function in neurodegenerative disorders and facilitate post-stroke recovery.
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Affiliation(s)
- Lori-An Etherington
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK
| | - Balázs Mihalik
- Biotalentum Kft, Gödöllő, Aulich Lajos u. 26, 2100, Hungary
| | | | - István Ling
- Egis Pharmaceuticals PLC, H1106, Budapest, Pf.100, Hungary
| | | | | | - Péter Varga
- Egis Pharmaceuticals PLC, H1106, Budapest, Pf.100, Hungary
| | - Ben G Gunn
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK
| | - Adam R Brown
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK
| | - Matthew R Livesey
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK
| | - Olivia Monteiro
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK
| | - Delia Belelli
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK
| | | | - Michael Spedding
- Institut de Recherches Servier, Croissy-sur-Seine, 78290, France
| | | | | | - Jeremy J Lambert
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, DD19SY, Scotland, UK.
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26
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Di Lazzaro V, Rothwell J, Capogna M. Noninvasive Stimulation of the Human Brain: Activation of Multiple Cortical Circuits. Neuroscientist 2017; 24:246-260. [DOI: 10.1177/1073858417717660] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Noninvasive brain stimulation methods, such as transcranial electric stimulation and transcranial magnetic stimulation are widely used tools for both basic research and clinical applications. However, the cortical circuits underlying their effects are poorly defined. Here we review the current knowledge based on data mostly coming from experiments performed on human subjects, and also to a lesser extent on rodent or primate models. The data suggest that multiple mechanisms are likely to be involved, such as the direct activation of layer V pyramidal neurons, but also of different types of GABAergic interneurons. In this regard, we propose a key role for a specific type of interneuron known as neurogliaform cell.
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Affiliation(s)
- Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico di Roma, Rome, Italy
- Fondazione Alberto Sordi–Research Institute for Ageing, Rome, Italy
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- The Danish Research Institute of Translational Neuroscience–DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Aarhus, Denmark
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27
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Assous M, Kaminer J, Shah F, Garg A, Koós T, Tepper JM. Differential processing of thalamic information via distinct striatal interneuron circuits. Nat Commun 2017; 8:15860. [PMID: 28604688 PMCID: PMC5477498 DOI: 10.1038/ncomms15860] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/03/2017] [Indexed: 11/23/2022] Open
Abstract
Recent discoveries of striatal GABAergic interneurons require a new conceptualization of the organization of intrastriatal circuitry and their cortical and thalamic inputs. We investigated thalamic inputs to the two populations of striatal neuropeptide Y (NPY) interneurons, plateau low threshold spike (PLTS) and NPY-neurogliaform (NGF) cells. Optogenetic activation of parafascicular inputs evokes suprathreshold monosynaptic glutamatergic excitation in NGF interneurons and a disynaptic, nicotinic excitation through cholinergic interneurons. In contrast, the predominant response of PLTS interneurons is a disynaptic inhibition dependent on thalamic activation of striatal tyrosine hydroxylase interneurons (THINs). In contrast, THINs do not innervate NGF or fast spiking interneurons, showing significant specificity in THINs outputs. Chemospecific ablation of THINs impairs prepulse inhibition of the acoustic startle response suggesting an important behavioural role of this disynaptic pathway. Our findings demonstrate that the impact of the parafascicular nucleus on striatal activity and some related behaviour critically depend on synaptic interactions within interneuronal circuits. The responses of striatal GABAergic interneurons to thalamic inputs are not well characterised. Here, the authors demonstrate that complex intrastriatal circuitry is responsible for thalamic-evoked monosynaptic and disynaptic excitation in NPY-NGF interneurons but a disynaptic inhibition in the NPY-PLTS.
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Affiliation(s)
- Maxime Assous
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA
| | - Jaime Kaminer
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA
| | - Fulva Shah
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA
| | - Arpan Garg
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA
| | - Tibor Koós
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA
| | - James M Tepper
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102, USA
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28
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Bezaire MJ, Raikov I, Burk K, Vyas D, Soltesz I. Interneuronal mechanisms of hippocampal theta oscillations in a full-scale model of the rodent CA1 circuit. eLife 2016; 5:e18566. [PMID: 28009257 DOI: 10.7554/elife.18566.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 12/15/2016] [Indexed: 05/25/2023] Open
Abstract
The hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the rodent CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct interneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation. These simulations reveal new insights into the spatiotemporal organization of the CA1 circuit during theta oscillations.
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Affiliation(s)
- Marianne J Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Raikov
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
- Department of Neurosurgery, Stanford University, Stanford, United States
| | - Kelly Burk
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Dhrumil Vyas
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, United States
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29
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Bezaire MJ, Raikov I, Burk K, Vyas D, Soltesz I. Interneuronal mechanisms of hippocampal theta oscillations in a full-scale model of the rodent CA1 circuit. eLife 2016; 5. [PMID: 28009257 PMCID: PMC5313080 DOI: 10.7554/elife.18566] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 12/15/2016] [Indexed: 12/16/2022] Open
Abstract
The hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the rodent CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct interneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation. These simulations reveal new insights into the spatiotemporal organization of the CA1 circuit during theta oscillations. DOI:http://dx.doi.org/10.7554/eLife.18566.001
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Affiliation(s)
- Marianne J Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Raikov
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States.,Department of Neurosurgery, Stanford University, Stanford, United States
| | - Kelly Burk
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Dhrumil Vyas
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, United States
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30
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Tasic B, Menon V, Nguyen TN, Kim TK, Jarsky T, Yao Z, Levi B, Gray LT, Sorensen SA, Dolbeare T, Bertagnolli D, Goldy J, Shapovalova N, Parry S, Lee C, Smith K, Bernard A, Madisen L, Sunkin SM, Hawrylycz M, Koch C, Zeng H. Adult mouse cortical cell taxonomy revealed by single cell transcriptomics. Nat Neurosci 2016; 19:335-46. [PMID: 26727548 PMCID: PMC4985242 DOI: 10.1038/nn.4216] [Citation(s) in RCA: 1067] [Impact Index Per Article: 133.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/03/2015] [Indexed: 12/13/2022]
Abstract
Nervous systems are composed of various cell types, but the extent of cell type diversity is poorly understood. Here, we construct a cellular taxonomy of one cortical region, primary visual cortex, in adult mice based on single cell RNA-sequencing. We identify 49 transcriptomic cell types including 23 GABAergic, 19 glutamatergic and seven non-neuronal types. We also analyze cell-type specific mRNA processing and characterize genetic access to these transcriptomic types by many transgenic Cre lines. Finally, we show that some of our transcriptomic cell types display specific and differential electrophysiological and axon projection properties, thereby confirming that the single cell transcriptomic signatures can be associated with specific cellular properties.
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Affiliation(s)
- Bosiljka Tasic
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Vilas Menon
- Allen Institute for Brain Science, Seattle, Washington, USA
| | | | - Tae Kyung Kim
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Tim Jarsky
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Zizhen Yao
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Boaz Levi
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Lucas T Gray
- Allen Institute for Brain Science, Seattle, Washington, USA
| | | | - Tim Dolbeare
- Allen Institute for Brain Science, Seattle, Washington, USA
| | | | - Jeff Goldy
- Allen Institute for Brain Science, Seattle, Washington, USA
| | | | - Sheana Parry
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Changkyu Lee
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Kimberly Smith
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Amy Bernard
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Linda Madisen
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Susan M Sunkin
- Allen Institute for Brain Science, Seattle, Washington, USA
| | | | - Christof Koch
- Allen Institute for Brain Science, Seattle, Washington, USA
| | - Hongkui Zeng
- Allen Institute for Brain Science, Seattle, Washington, USA
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31
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Lőrincz T, Kisfali M, Lendvai B, Sylvester Vizi E. Phenotype-dependent Ca(2+) dynamics in single boutons of various anatomically identified GABAergic interneurons in the rat hippocampus. Eur J Neurosci 2015; 43:536-47. [PMID: 26566266 PMCID: PMC5064611 DOI: 10.1111/ejn.13131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/14/2015] [Accepted: 11/04/2015] [Indexed: 02/02/2023]
Abstract
Interneurons (INs) of the hippocampus exert versatile inhibition on pyramidal cells by silencing the network at different oscillation frequencies. Although IN discharge can phase-lock to various rhythms in the hippocampus, under high-frequency axon firing, the boutons may not be able to follow the fast activity. Here, we studied Ca(2+) responses to action potentials (APs) in single boutons using combined two-photon microscopy and patch clamp electrophysiology in three types of INs: non-fast-spiking (NFS) neurons showing cannabinoid 1 receptor labelling and dendrite targeting, fast-spiking partially parvalbumin-positive cells synapsing with dendrites (DFS), and parvalbumin-positive cells with perisomatic innervation (PFS). The increase in [Ca(2+) ]i from AP trains was substantially higher in NFS boutons than in DFS or PFS boutons. The decay of bouton Ca(2+) responses was markedly faster in DFS and PFS cells compared with NFS neurons. The bouton-to-bouton variability of AP-evoked Ca(2+) transients in the same axon was surprisingly low in each cell type. Importantly, local responses were saturated after shorter trains of APs in NFS cells than in PFS cells. This feature of fast-spiking neurons might allow them to follow higher-frequency gamma oscillations for a longer time than NFS cells. The function of NFS boutons may better support asynchronous GABA release. In conclusion, we demonstrate several neuron-specific Ca(2+) transients in boutons of NFS, PFS and DFS neurons, which may serve differential functions in hippocampal networks.
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Affiliation(s)
- Tibor Lőrincz
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony str. 43., Budapest, 1083, Hungary
| | - Máté Kisfali
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony str. 43., Budapest, 1083, Hungary
| | - Balázs Lendvai
- Gedeon Richter Plc, Pharmacology and Drug Safety, Budapest, Hungary
| | - Elek Sylvester Vizi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony str. 43., Budapest, 1083, Hungary.,Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
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32
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Abstract
Recent research into local-circuit GABAergic inhibitory interneurons of the mammalian central nervous system has provided unprecedented insight into the mechanics of neuronal circuitry and its dysfunction. Inhibitory interneurons consist of a broad array of anatomically and neurochemically diverse cell types, and this suggests that each occupies an equally diverse functional role. Although neurogliaform cells were observed by Cajal over a century ago, our understanding of the functional role of this class of interneurons is in its infancy. However, it is rapidly becoming clear that this cell type operates under a distinct repertoire of rules to provide novel forms of inhibitory control of numerous afferent pathways.
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33
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Allene C, Lourenço J, Bacci A. The neuronal identity bias behind neocortical GABAergic plasticity. Trends Neurosci 2015; 38:524-34. [PMID: 26318208 DOI: 10.1016/j.tins.2015.07.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 12/18/2022]
Abstract
In the neocortex, different types of excitatory and inhibitory neurons connect to one another following a detailed blueprint, defining functionally-distinct subnetworks, whose activity and modulation underlie complex cognitive functions. We review the cell-autonomous plasticity of perisomatic inhibition onto principal excitatory neurons. We propose that the tendency of different cortical layers to exhibit depression or potentiation of perisomatic inhibition is dictated by the specific identities of principal neurons (PNs). These are mainly defined by their projection targets and by their preference to be innervated by specific perisomatic-targeting basket cell types. Therefore, principal neurons responsible for relaying information to subcortical nuclei are differentially inhibited and show specific forms of plasticity compared to other PNs that are specialized in more associative functions.
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Affiliation(s)
- Camille Allene
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC Paris 6), Unité Mixte de Recherche S 1127; Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1127; Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 7225; Institut du Cerveau et de la Moelle épinière (ICM), 75013 Paris, France
| | - Joana Lourenço
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC Paris 6), Unité Mixte de Recherche S 1127; Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1127; Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 7225; Institut du Cerveau et de la Moelle épinière (ICM), 75013 Paris, France
| | - Alberto Bacci
- Sorbonne Universités, Université Pierre et Marie Curie (UPMC Paris 6), Unité Mixte de Recherche S 1127; Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1127; Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche 7225; Institut du Cerveau et de la Moelle épinière (ICM), 75013 Paris, France.
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34
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Prokic EJ, Weston C, Yamawaki N, Hall SD, Jones RS, Stanford IM, Ladds G, Woodhall GL. Cortical oscillatory dynamics and benzodiazepine-site modulation of tonic inhibition in fast spiking interneurons. Neuropharmacology 2015; 95:192-205. [DOI: 10.1016/j.neuropharm.2015.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/09/2015] [Accepted: 03/08/2015] [Indexed: 11/16/2022]
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35
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Ling I, Mihalik B, Etherington LA, Kapus G, Pálvölgyi A, Gigler G, Kertész S, Gaál A, Pallagi K, Kiricsi P, Szabó É, Szénási G, Papp L, Hársing LG, Lévay G, Spedding M, Lambert JJ, Belelli D, Barkóczy J, Volk B, Simig G, Gacsályi I, Antoni FA. A novel GABA(A) alpha 5 receptor inhibitor with therapeutic potential. Eur J Pharmacol 2015; 764:497-507. [PMID: 26169564 DOI: 10.1016/j.ejphar.2015.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 10/23/2022]
Abstract
Novel 2,3-benzodiazepine and related isoquinoline derivatives, substituted at position 1 with a 2-benzothiophenyl moiety, were synthesized to produce compounds that potently inhibited the action of GABA on heterologously expressed GABAA receptors containing the alpha 5 subunit (GABAA α5), with no apparent affinity for the benzodiazepine site. Substitutions of the benzothiophene moiety at position 4 led to compounds with drug-like properties that were putative inhibitors of extra-synaptic GABAA α5 receptors and had substantial blood-brain barrier permeability. Initial characterization in vivo showed that 8-methyl-5-[4-(trifluoromethyl)-1-benzothiophen-2-yl]-1,9-dihydro-2H-[1,3]oxazolo[4,5-h][2,3]benzodiazepin-2-one was devoid of sedative, pro-convulsive or motor side-effects, and enhanced the performance of rats in the object recognition test. In summary, we have discovered a first-in-class GABA-site inhibitor of extra-synaptic GABAA α5 receptors that has promising drug-like properties and warrants further development.
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Affiliation(s)
- István Ling
- Chemical Research Division, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Balázs Mihalik
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Lori-An Etherington
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, Scotland, UK
| | - Gábor Kapus
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Adrienn Pálvölgyi
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Gábor Gigler
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Szabolcs Kertész
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Attila Gaál
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Katalin Pallagi
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Péter Kiricsi
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Éva Szabó
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Gábor Szénási
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Lilla Papp
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - László G Hársing
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - György Lévay
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | | | - Jeremy J Lambert
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, Scotland, UK
| | - Delia Belelli
- Division of Neuroscience, Medical Research Institute, Ninewells Hospital & Medical School, Dundee University, Dundee, Scotland, UK
| | - József Barkóczy
- Chemical Research Division, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Balázs Volk
- Chemical Research Division, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Gyula Simig
- Chemical Research Division, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - István Gacsályi
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary
| | - Ferenc A Antoni
- Division of Preclinical Research, Egis Pharmaceuticals PLC, Budapest, Hungary.
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36
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Bohbot JD, Pitts RJ. The narrowing olfactory landscape of insect odorant receptors. Front Ecol Evol 2015. [DOI: 10.3389/fevo.2015.00039] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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37
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Labrakakis C, Rudolph U, De Koninck Y. The heterogeneity in GABAA receptor-mediated IPSC kinetics reflects heterogeneity of subunit composition among inhibitory and excitatory interneurons in spinal lamina II. Front Cell Neurosci 2014; 8:424. [PMID: 25565959 PMCID: PMC4263102 DOI: 10.3389/fncel.2014.00424] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 11/24/2014] [Indexed: 12/03/2022] Open
Abstract
GABAergic inhibition displays rich functional diversity throughout the CNS, which arises from variations in the nature of inputs, subunit composition, subcellular localization of receptors and synapse geometry, or reuptake mechanisms. In the spinal dorsal horn (SDH), GABAA and glycine receptors play a major role in the control of excitability and accuracy of nociceptive processing. Identifying which components shape the properties of the inhibitory synapses in different cell types is necessary to understand how nociceptive information is integrated. To address this, we used transgenic mice where inhibitory interneurons express GAD65-EGFP. We found that GABAA, but not glycine receptor-mediated evoked IPSCs displayed slower kinetics in EGFP+ vs. EGFP− interneurons. GABAA miniature IPSC decay kinetics showed a large variability in both populations, however the distribution of decays differed between EGFP+ and EGFP− interneurons. The range of mIPSC decay kinetics observed was replicated in experiments using rapid application of GABA on outside-out patches taken from SDH neurons in slices. Furthermore, GABAA decay kinetics were not affected by uptake blockers and were not different in mice lacking δ or α5 subunits, indicating that intrinsic channel properties likely underlie the heterogeneity. To identify whether other α subunits shape the various kinetic properties observed we took advantage of knock-in mice carrying point mutations in either the α1, α2, or α3 subunits rendering Ro 15-4513 a selective agonist at the benzodiazepine modulatory site. We found that α1 and α2 subunit underlie the fast decaying component of IPSCs while the slow component is determined by the α3 subunit. The differential distribution of GABAA subunits at inhibitory synapses thus sculpts the heterogeneity of the SDH inhibitory circuitry. This diversity of inhibitory elements can be harnessed to selectively modulate different components of the spinal nociceptive circuitry for therapeutic interventions.
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Affiliation(s)
- Charalampos Labrakakis
- Unité de Neurosciences Cellulaires et Moléculaire, Institut Universitaire en Santé Mentale de Québec Québec, QC, Canada ; Department of Biological Applications and Technology, University of Ioannina Ioannina, Greece
| | - Uwe Rudolph
- Laboratory of Genetic Neuropharmacology, McLean Hospital, and Department of Psychiatry, Harvard Medical School Belmont, MA, USA
| | - Yves De Koninck
- Unité de Neurosciences Cellulaires et Moléculaire, Institut Universitaire en Santé Mentale de Québec Québec, QC, Canada ; Department of Psychiatry and Neuroscience, Université Laval Québec, QC, Canada
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38
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Optogenetic activation of cajal-retzius cells reveals their glutamatergic output and a novel feedforward circuit in the developing mouse hippocampus. J Neurosci 2014; 34:13018-32. [PMID: 25253849 DOI: 10.1523/jneurosci.1407-14.2014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cajal-Retzius cells orchestrate the development of cortical circuits by secreting the glycoprotein reelin. However, their computational functions are still unknown. In fact, the nature of their postsynaptic targets, major neurotransmitter released, as well as the class of postsynaptic receptors activated by their firing remain unclear. Here, we have addressed these questions by activating Cajal-Retzius cells optogenetically in mouse hippocampal slices. Light delivered to stratum lacunosum-moleculare triggered EPSCs both on local interneurons and on pyramidal cells. Responses recorded under voltage-clamp conditions had identical short latencies and similar amplitudes, but were kinetically different (i.e., faster in interneurons vs pyramidal cells). In both cases, responses were blocked by TTX, indicating that they were generated by action potential-dependent release. Responses in interneurons were rescued by the addition of 4-AP to TTX, and decreased when presynaptic firing in Cajal-Retzius cells was reduced by the chemokine CXCL12, indicating the existence of a direct Cajal-Retzius cell-interneuron monosynaptic connection. Although the combined application of 4-AP and TTX did not rescue responses in pyramidal cells, neither were they affected by the GABAA receptor blocker gabazine, which would be expected if they were polysynaptic. Both connections showed physiological and pharmacological properties indicating the involvement of AMPA- and NMDA-type glutamate receptors. The connectivity from presynaptic Cajal-Retzius cells to interneurons was strong enough to generate long-latency feedforward GABAergic input onto pyramidal cells. We propose that this newly defined Cajal-Retzius cell-dependent microcircuit may regulate synaptic plasticity and dendritic development in stratum lacunosum-moleculare, thus impacting the integrative properties of the developing hippocampus.
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Khakhalin AS, Koren D, Gu J, Xu H, Aizenman CD. Excitation and inhibition in recurrent networks mediate collision avoidance in Xenopus tadpoles. Eur J Neurosci 2014; 40:2948-62. [PMID: 24995793 DOI: 10.1111/ejn.12664] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/23/2014] [Accepted: 05/28/2014] [Indexed: 01/24/2023]
Abstract
Information processing in the vertebrate brain is thought to be mediated through distributed neural networks, but it is still unclear how sensory stimuli are encoded and detected by these networks, and what role synaptic inhibition plays in this process. Here we used a collision avoidance behavior in Xenopus tadpoles as a model for stimulus discrimination and recognition. We showed that the visual system of the tadpole is selective for behaviorally relevant looming stimuli, and that the detection of these stimuli first occurs in the optic tectum. By comparing visually guided behavior, optic nerve recordings, excitatory and inhibitory synaptic currents, and the spike output of tectal neurons, we showed that collision detection in the tadpole relies on the emergent properties of distributed recurrent networks within the tectum. We found that synaptic inhibition was temporally correlated with excitation, and did not actively sculpt stimulus selectivity, but rather it regulated the amount of integration between direct inputs from the retina and recurrent inputs from the tectum. Both pharmacological suppression and enhancement of synaptic inhibition disrupted emergent selectivity for looming stimuli. Taken together these findings suggested that, by regulating the amount of network activity, inhibition plays a critical role in maintaining selective sensitivity to behaviorally-relevant visual stimuli.
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Affiliation(s)
- Arseny S Khakhalin
- Department of Neuroscience, Brown University, Box G-LN, Providence, RI, 02912, USA
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Modulation of behavioral networks by selective interneuronal inactivation. Mol Psychiatry 2014; 19:580-7. [PMID: 24322205 PMCID: PMC4179403 DOI: 10.1038/mp.2013.167] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/04/2013] [Accepted: 10/17/2013] [Indexed: 12/15/2022]
Abstract
Gamma-aminobutyric acid (GABA)-ergic disturbances are hallmark features of schizophrenia and other neuropsychiatric disorders and encompass multiple interneuronal cell types. Using bacterial artificial chromosome-driven, miRNA silencing technology we generated transgenic mouse lines that suppress glutamic acid decarboxylase 1 (GAD1) in either cholecystokinin (CCK)- or neuropeptide Y (NPY)-expressing interneurons. In situ lipidomic and proteomic analyses on brain tissue sections revealed distinct, brain region-specific profiles in each transgenic line. Behavioral analyses revealed that suppression of GAD1 in CCK+ interneurons resulted in locomotor and olfactory sensory changes, whereas suppression in NPY+ interneurons affected anxiety-related behaviors and social interaction. Both transgenic mouse lines had altered sensitivity to amphetamine albeit in opposite directions. Together, these data argue that reduced GAD1 expression leads to altered molecular and behavioral profiles in a cell type-dependent manner, and that these subpopulations of interneurons are strong and opposing modulators of dopamine system function. Furthermore, our findings also support the hypothesis that neuronal networks are differentially controlled by diverse inhibitory subnetworks.
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Suzuki N, Tang CSM, Bekkers JM. Persistent barrage firing in cortical interneurons can be induced in vivo and may be important for the suppression of epileptiform activity. Front Cell Neurosci 2014; 8:76. [PMID: 24659955 PMCID: PMC3952511 DOI: 10.3389/fncel.2014.00076] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 02/21/2014] [Indexed: 11/13/2022] Open
Abstract
Neural circuits are typically maintained in a state of dynamic equilibrium by balanced synaptic excitation and inhibition. However, brain regions that are particularly susceptible to epilepsy may have evolved additional specialized mechanisms for inhibiting over-excitation. Here we identify one such possible mechanism in the cerebral cortex and hippocampus of mice. Recently it was reported that some types of GABAergic interneurons can slowly integrate excitatory inputs until eventually they fire persistently in the absence of the original stimulus. This property, called persistent firing or retroaxonal barrage firing (BF), is of unknown physiological importance. We show that two common types of interneurons in cortical regions, neurogliaform (NG) cells and fast-spiking (FS) cells, are unique in exhibiting BF in acute slices (~85 and ~23% success rate for induction, respectively). BF can also be induced in vivo, although the success rate for induction is lower (~60% in NG cells). In slices, BF could reliably be triggered by trains of excitatory synaptic input, as well as by exposure to proconvulsant bath solutions (elevated extracellular K(+), blockade of GABAA receptors). Using pair recordings in slices, we confirmed that barrage-firing NG cells can produce synaptic inhibition of nearby pyramidal neurons, and that this inhibition outlasts the original excitation. The ubiquity of NG and FS cells, together with their ability to fire persistently following excessive excitation, suggests that these interneurons may function as cortical sentinels, imposing an activity-dependent brake on undesirable neuronal hyperexcitability.
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Affiliation(s)
- Norimitsu Suzuki
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia
| | - Clara S-M Tang
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia
| | - John M Bekkers
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra ACT, Australia
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Abstract
Little is known about how neuron firing recorded in vivo retrogradely influences synaptic strength. We injected the firing of a rat hippocampal neurogliaform cell (NGFC), a widely expressed GABAergic neuron type, detected in vivo during theta rhythm, into NGFCs of rat or neuronal nitric oxide synthase (nNOS)-Cre-tdTomato mouse recorded in vitro. We found that the "in vivo firing pattern" produced a transient firing-induced suppression of synaptic inhibition (FSI) evoked by a presynaptic NGFC. Imaging experiments demonstrate that FSI was associated with action potential backpropagation (bAP) and a supralinear increase in dendritic Ca(2+). The application of the L-type Ca(2+) channel antagonist nimodipine blocked FSI. Further pharmacological experiments, such as the application of a nitric oxide-sensitive guanylyl cyclase (NO-sGC) receptor antagonist, a NOS inhibitor, and NO donors, suggested that NO released from postsynaptic cells mediated FSI and likely activated presynaptic receptors to inhibit GABA release. The in vivo firing pattern modulated the size of unitary EPSPs impinging on NGFCs through FSI and not via a direct effect on excitatory synaptic transmission. Our data demonstrate: (1) retrograde signaling initiated by in vivo firing pattern, (2) interneuron bAPs detected with fast temporal resolution, and (3) a novel role for NO expressed by specific interneuron types.
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Extrasynaptic GABA(A) receptors couple presynaptic activity to postsynaptic inhibition in the somatosensory thalamus. J Neurosci 2013; 33:14850-68. [PMID: 24027285 DOI: 10.1523/jneurosci.1174-13.2013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Thalamocortical circuits govern cognitive, sensorimotor, and sleep-related network processes, and generate pathological activities during absence epilepsy. Inhibitory control of thalamocortical (TC) relay neurons is partially mediated by GABA released from neurons of the thalamic reticular nucleus (nRT), acting predominantly via synaptic α1β2γ2 GABA(A) receptors (GABA(A)Rs). Importantly, TC neurons also express extrasynaptic α4β2δ GABA(A)Rs, although how they cooperate with synaptic GABA(A)Rs to influence relay cell inhibition, particularly during physiologically relevant nRT output, is unknown. To address this question, we performed paired whole-cell recordings from synaptically coupled nRT and TC neurons of the ventrobasal (VB) complex in brain slices derived from wild-type and extrasynaptic GABA(A)R-lacking, α4 "knock-out" (α4(0/0)) mice. We demonstrate that the duration of VB phasic inhibition generated in response to nRT burst firing is greatly reduced in α4(0/0) pairs, suggesting that action potential-dependent phasic inhibition is prolonged by recruitment of extrasynaptic GABA(A)Rs. Furthermore, the influence of nRT tonic firing frequency on VB holding current is also greatly reduced in α4(0/0) pairs, implying that the α4-GABA(A)R-mediated tonic conductance of relay neurons is dynamically influenced, in an activity-dependent manner, by nRT tonic firing intensity. Collectively, our data reveal that extrasynaptic GABA(A)Rs of the somatosensory thalamus do not merely provide static tonic inhibition but can also be dynamically engaged to couple presynaptic activity to postsynaptic excitability. Moreover, these processes are highly sensitive to the δ-selective allosteric modulator, DS2 and manipulation of GABA transport systems, revealing novel opportunities for therapeutic intervention in thalamocortical network disorders.
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Novel GABAergic circuits mediating excitation/inhibition of Cajal-Retzius cells in the developing hippocampus. J Neurosci 2013; 33:5486-98. [PMID: 23536064 DOI: 10.1523/jneurosci.5680-12.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cajal-Retzius cells are a class of neurons believed to play critical roles during cortical development. However, their network computational functions remain poorly understood. Although work in the neocortex and hippocampus has shown that Cajal-Retzius cells receive predominantly, if not exclusively, spontaneous GABA(A) receptor-mediated input, the cellular sources originating these events remain unclear. However, a precise definition of the presynaptic GABAergic interneurons contacting Cajal-Retzius cells is important to understand the microcircuits and network patterns controlling their activation. Here, we have taken advantage of electrophysiological and anatomical techniques applied to mouse hippocampal slices in vitro to directly address this question. Our paired recording experiments indicate that Cajal-Retzius cells receive small-amplitude, kinetically slow synaptic input from stratum lacunosum-moleculare interneurons, anatomically identified as neurogliaform cells. In addition, a convergence of optogenetic, electrophysiological, and pharmacological experiments shows that Cajal-Retzius cells receive GABAergic input from oriens lacunosum-moleculare cells and that this input has different physiological properties (i.e., larger amplitude and faster kinetics) from the one provided by neurogliaform cells. Last, we show that GABAergic evoked synaptic input onto Cajal-Retzius cells may either increase their excitability and trigger action potentials or inhibit spontaneous firing by depolarization block. We propose that the specific type of response depends on both the membrane potential of Cajal-Retzius cells and the kinetics of the received GABAergic input. In conclusion, we have unraveled a novel hippocampal microcircuit with complex GABAergic synaptic signaling, which we suggest may play a role in the refinement of the hippocampal network and connections during development.
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Dieni CV, Chancey JH, Overstreet-Wadiche LS. Dynamic functions of GABA signaling during granule cell maturation. Front Neural Circuits 2013; 6:113. [PMID: 23316139 PMCID: PMC3539683 DOI: 10.3389/fncir.2012.00113] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 12/11/2012] [Indexed: 12/23/2022] Open
Abstract
The dentate gyrus is one of the few areas of the brain where new neurons are generated throughout life. Neural activity influences multiple stages of neurogenesis, thereby allowing experience to regulate the production of new neurons. It is now well established that GABAA receptor-mediated signaling plays a pivotal role in mediating activity-dependent regulation of adult neurogenesis. GABA first acts as a trophic signal that depolarizes progenitors and early post mitotic granule cells, enabling network activity to control molecular cascades essential for proliferation, survival and growth. Following the development of glutamatergic synaptic inputs, GABA signaling switches from excitatory to inhibitory. Thereafter robust synaptic inhibition enforces low spiking probability of granule cells in response to cortical excitatory inputs and maintains the sparse activity patterns characteristic of this brain region. Here we review these dynamic functions of GABA across granule cell maturation, focusing on the potential role of specific interneuron circuits at progressive developmental stages. We further highlight questions that remain unanswered about GABA signaling in granule cell development and excitability.
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Affiliation(s)
- Cristina V Dieni
- Department of Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA
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Neurogliaform cells dynamically regulate somatosensory integration via synapse-specific modulation. Nat Neurosci 2012; 16:13-5. [PMID: 23222912 DOI: 10.1038/nn.3284] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 11/18/2012] [Indexed: 11/08/2022]
Abstract
Despite the prevailing idea that neurogliaform cells produce a spatially unrestricted widespread inhibition, we demonstrate here that their activity attenuates thalamic-evoked feed-forward inhibition in layer IV barrel cortex but has no effect on feed-forward excitation. The result of this circuit selectivity is a dynamic regulation in the temporal window for integration of excitatory thalamic input, thus revealing a new role for neurogliaform cells in shaping sensory processing.
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Tricoire L, Vitalis T. Neuronal nitric oxide synthase expressing neurons: a journey from birth to neuronal circuits. Front Neural Circuits 2012; 6:82. [PMID: 23227003 PMCID: PMC3514612 DOI: 10.3389/fncir.2012.00082] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 10/25/2012] [Indexed: 12/17/2022] Open
Abstract
Nitric oxide (NO) is an important signaling molecule crucial for many physiological processes such as synaptic plasticity, vasomotricity, and inflammation. Neuronal nitric oxide synthase (nNOS) is the enzyme responsible for the synthesis of NO by neurons. In the juvenile and mature hippocampus and neocortex nNOS is primarily expressed by subpopulations of GABAergic interneurons. Over the past two decades, many advances have been achieved in the characterization of neocortical and hippocampal nNOS expressing neurons. In this review, we summarize past and present studies that have characterized the electrophysiological, morphological, molecular, and synaptic properties of these neurons. We also discuss recent studies that have shed light on the developmental origins and specification of GABAergic neurons with specific attention to neocortical and hippocampal nNOS expressing GABAergic neurons. Finally, we summarize the roles of NO and nNOS-expressing inhibitory neurons.
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Affiliation(s)
- Ludovic Tricoire
- CNRS-UMR 7102, Laboratoire de Neurobiologie des Processus Adaptatifs, Université Pierre et Marie Curie Paris, France
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Chamberland S, Topolnik L. Inhibitory control of hippocampal inhibitory neurons. Front Neurosci 2012; 6:165. [PMID: 23162426 PMCID: PMC3496901 DOI: 10.3389/fnins.2012.00165] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/24/2012] [Indexed: 11/13/2022] Open
Abstract
Information processing within neuronal networks is determined by a dynamic partnership between principal neurons and local circuit inhibitory interneurons. The population of GABAergic interneurons is extremely heterogeneous and comprises, in many brain regions, cells with divergent morphological and physiological properties, distinct molecular expression profiles, and highly specialized functions. GABAergic interneurons have been studied extensively during the past two decades, especially in the hippocampus, which is a relatively simple cortical structure. Different types of hippocampal inhibitory interneurons control spike initiation [e.g., axo-axonic and basket cells (BCs)] and synaptic integration (e.g., bistratified and oriens–lacunosum moleculare interneurons) within pyramidal neurons and synchronize local network activity, providing a means for functional segregation of neuronal ensembles and proper routing of hippocampal information. Thus, it is thought that, at least in the hippocampus, GABAergic inhibitory interneurons represent critical regulating elements at all stages of information processing, from synaptic integration and spike generation to large-scale network activity. However, this raises an important question: if inhibitory interneurons are fundamental for network computations, what are the mechanisms that control the activity of the interneurons themselves? Given the essential role of synaptic inhibition in the regulation of neuronal activity, it would be logical to expect that specific inhibitory mechanisms have evolved to control the operation of interneurons. Here, we review the mechanisms of synaptic inhibition of interneurons and discuss their role in the operation of hippocampal inhibitory circuits.
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Affiliation(s)
- Simon Chamberland
- Axis of Cellular and Molecular Neuroscience, IUSMQ, Department of Biochemistry, Microbiology and Bio-informatics, Université Laval Québec, QC, Canada
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Budisantoso T, Harada H, Kamasawa N, Fukazawa Y, Shigemoto R, Matsui K. Evaluation of glutamate concentration transient in the synaptic cleft of the rat calyx of Held. J Physiol 2012; 591:219-39. [PMID: 23070699 DOI: 10.1113/jphysiol.2012.241398] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Establishing the spatiotemporal concentration profile of neurotransmitter following synaptic vesicular release is essential for our understanding of inter-neuronal communication. Such profile is a determinant of synaptic strength, short-term plasticity and inter-synaptic crosstalk. Synaptically released glutamate has been suggested to reach a few millimolar in concentration and last for <1 ms. The synaptic cleft is often conceived as a single concentration compartment, whereas a huge gradient likely exists. Modelling studies have attempted to describe this gradient, but two key parameters, the number of glutamate in a vesicle (N(Glu)) and its diffusion coefficient (D(Glu)) in the extracellular space, remained unresolved. To determine this profile, the rat calyx of Held synapse at postnatal day 12-16 was studied where diffusion of glutamate occurs two-dimensionally and where quantification of AMPA receptor distribution on individual postsynaptic specialization on medial nucleus of the trapezoid body principal cells is possible using SDS-digested freeze-fracture replica labelling. To assess the performance of these receptors as glutamate sensors, a kinetic model of the receptors was constructed from outside-out patch recordings. From here, we simulated synaptic responses and compared them with the EPSC recordings. Combinations of N(Glu) and D(Glu) with an optimum of 7000 and 0.3 μm(2) ms(-1) reproduced the data, suggesting slow diffusion. Further simulations showed that a single vesicle does not saturate the synaptic receptors, and that glutamate spillover does not affect the conductance amplitude at this synapse. Using the estimated profile, we also evaluated how the number of multiple vesicle releases at individual active zones affects the amplitude of postsynaptic signals.
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Affiliation(s)
- Timotheus Budisantoso
- Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki 444-8787, Japan
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Mańko M, Bienvenu TCM, Dalezios Y, Capogna M. Neurogliaform cells of amygdala: a source of slow phasic inhibition in the basolateral complex. J Physiol 2012; 590:5611-27. [PMID: 22930272 DOI: 10.1113/jphysiol.2012.236745] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Synaptic inhibition in the amygdala actively participates in processing emotional information. To improve the understanding of interneurons in amygdala networks it is necessary to characterize the GABAergic cell types, their connectivity and physiological roles. We used a mouse line expressing a green fluorescent protein (GFP) under the neuropeptide Y (NPY) promoter. Paired recordings between presynaptic NPY-GFP-expressing (+) cells and postsynaptic principal neurons (PNs) of the basolateral amygdala (BLA) were performed. The NPY-GFP+ neurons displayed small somata and short dendrites embedded in a cloud of highly arborized axon, suggesting a neurogliaform cell (NGFC) type. We discovered that a NPY-GFP+ cell evoked a GABA(A) receptor-mediated slow inhibitory postsynaptic current (IPSC) in a PN and an autaptic IPSC. The slow kinetics of these IPSCs was likely caused by the low concentration and spillover of extracellular GABA. We also report that NGFCs of the BLA fired action potentials phase-locked to hippocampal theta oscillations in anaesthetized rats. When this firing was re-played in NPY+-NGFCs in vitro, it evoked a transient depression of the IPSCs. Presynaptic GABA(B) receptors and functional depletion of synaptic vesicles determined this short-term plasticity. Synaptic contacts made by recorded NGFCs showed close appositions, and rarely identifiable classical synaptic structures. Thus, we report here a novel interneuron type of the amygdala that generates volume transmission of GABA. The peculiar functional mode of NGFCs makes them unique amongst all GABAergic cell types of the amygdala identified so far.
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Affiliation(s)
- Mirosława Mańko
- MRC Anatomical Neuropharmacology Unit, Mansfield Road, Oxford OX1 3TH, UK
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