1
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Chiovini B, Pálfi D, Majoros M, Juhász G, Szalay G, Katona G, Szőri M, Frigyesi O, Lukácsné Haveland C, Szabó G, Erdélyi F, Máté Z, Szadai Z, Madarász M, Dékány M, Csizmadia IG, Kovács E, Rózsa B, Mucsi Z. Theoretical Design, Synthesis, and In Vitro Neurobiological Applications of a Highly Efficient Two-Photon Caged GABA Validated on an Epileptic Case. ACS OMEGA 2021; 6:15029-15045. [PMID: 34151084 PMCID: PMC8210458 DOI: 10.1021/acsomega.1c01164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/20/2021] [Indexed: 06/13/2023]
Abstract
In this paper, we present an additional, new cage-GABA compound, called 4-amino-1-(4'-dimethylaminoisopropoxy-5',7'-dinitro-2',3'-dihydro-indol-1-yl)-1-oxobutane-γ-aminobutyric acid (iDMPO-DNI-GABA), and currently, this compound is the only photoreagent, which can be applied for GABA uncaging without experimental compromises. By a systematic theoretical design and successful synthesis of several compounds, the best reagent exhibits a high two-photon efficiency within the 700-760 nm range with excellent pharmacological behavior, which proved to be suitable for a complex epileptic study. Quantum chemical design showed that the optimal length of the cationic side chain enhances the two-photon absorption by 1 order of magnitude due to the cooperating internal hydrogen bonding to the extra nitro group on the core. This feature increased solubility while suppressing membrane permeability. The efficiency was demonstrated in a systematic, wide range of in vitro single-cell neurophysiological experiments by electrophysiological as well as calcium imaging techniques. Scalable inhibitory ion currents were elicited by iDMPO-DNI-GABA with appropriate spatial-temporal precision, blocking both spontaneous and evoked cell activity with excellent efficiency. Additionally, to demonstrate its applicability in a real neurobiological study, we could smoothly and selectively modulate neuronal activities during artificial epileptic rhythms first time in a neural network of GCaMP6f transgenic mouse brain slices.
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Affiliation(s)
- Balázs Chiovini
- The
Faculty of Information Technology, Pázmány
Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary
- Laboratory
of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Dénes Pálfi
- The
Faculty of Information Technology, Pázmány
Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary
| | - Myrtill Majoros
- The
Faculty of Information Technology, Pázmány
Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary
| | - Gábor Juhász
- The
Faculty of Information Technology, Pázmány
Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary
- Laboratory
of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Gergely Szalay
- Laboratory
of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Gergely Katona
- Laboratory
of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Milán Szőri
- Institute
of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, H-3515 Miskolc, Hungary
| | - Orsolya Frigyesi
- Chemistry
Department, Femtonics Limited, Tűzoltó str. 59, H-1094 Budapest, Hungary
| | | | - Gábor Szabó
- Transgenic
Facility, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Ferenc Erdélyi
- Transgenic
Facility, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Zoltán Máté
- Transgenic
Facility, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Zoltán Szadai
- The
Faculty of Information Technology, Pázmány
Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary
| | - Miklós Madarász
- Laboratory
of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Miklós Dékány
- Gedeon Richter
Plc, Gyömrői
str. 19-21, H-1103 Budapest, Hungary
| | - Imre G. Csizmadia
- Department
of Chemistry, University of Toronto, 80 St. George Street, M5S 3H6 Toronto, Ontario, Canada
| | - Ervin Kovács
- Chemistry
Department, Femtonics Limited, Tűzoltó str. 59, H-1094 Budapest, Hungary
- Institute
of Materials and Environmental Chemistry, Research Centre for Natural Sciences, 2 Magyar tudósok körútja, H-1117 Budapest, Hungary
| | - Balázs Rózsa
- The
Faculty of Information Technology, Pázmány
Péter Catholic University, 50 Práter str., H-1083 Budapest, Hungary
- Laboratory
of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, 43 Szigony str., H-1083 Budapest, Hungary
| | - Zoltán Mucsi
- Institute
of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, H-3515 Miskolc, Hungary
- Chemistry
Department, Femtonics Limited, Tűzoltó str. 59, H-1094 Budapest, Hungary
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2
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Roberts BM, Lopes EF, Cragg SJ. Axonal Modulation of Striatal Dopamine Release by Local γ-Aminobutyric Acid (GABA) Signalling. Cells 2021; 10:709. [PMID: 33806845 PMCID: PMC8004767 DOI: 10.3390/cells10030709] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Striatal dopamine (DA) release is critical for motivated actions and reinforcement learning, and is locally influenced at the level of DA axons by other striatal neurotransmitters. Here, we review a wealth of historical and more recently refined evidence indicating that DA output is inhibited by striatal γ-aminobutyric acid (GABA) acting via GABAA and GABAB receptors. We review evidence supporting the localisation of GABAA and GABAB receptors to DA axons, as well as the identity of the striatal sources of GABA that likely contribute to GABAergic modulation of DA release. We discuss emerging data outlining the mechanisms through which GABAA and GABAB receptors inhibit the amplitude as well as modulate the short-term plasticity of DA release. Furthermore, we highlight recent data showing that DA release is governed by plasma membrane GABA uptake transporters on striatal astrocytes, which determine ambient striatal GABA tone and, by extension, the tonic inhibition of DA release. Finally, we discuss how the regulation of striatal GABA-DA interactions represents an axis for dysfunction in psychomotor disorders associated with dysregulated DA signalling, including Parkinson's disease, and could be a novel therapeutic target for drugs to modify striatal DA output.
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Affiliation(s)
| | | | - Stephanie J. Cragg
- Department of Physiology, Anatomy and Genetics, Centre for Integrative Neuroscience and Oxford Parkinson’s Disease Centre, University of Oxford, Oxford OX1 3PT, UK
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3
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Kramer PF, Twedell EL, Shin JH, Zhang R, Khaliq ZM. Axonal mechanisms mediating γ-aminobutyric acid receptor type A (GABA-A) inhibition of striatal dopamine release. eLife 2020; 9:e55729. [PMID: 32870779 PMCID: PMC7462615 DOI: 10.7554/elife.55729] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/15/2020] [Indexed: 01/03/2023] Open
Abstract
Axons of dopaminergic neurons innervate the striatum where they contribute to movement and reinforcement learning. Past work has shown that striatal GABA tonically inhibits dopamine release, but whether GABA-A receptors directly modulate transmission or act indirectly through circuit elements is unresolved. Here, we use whole-cell and perforated-patch recordings to test for GABA-A receptors on the main dopaminergic neuron axons and branching processes within the striatum of adult mice. Application of GABA depolarized axons, but also decreased the amplitude of axonal spikes, limited propagation and reduced striatal dopamine release. The mechanism of inhibition involved sodium channel inactivation and shunting. Lastly, we show the positive allosteric modulator diazepam enhanced GABA-A currents on dopaminergic axons and directly inhibited release, but also likely acts by reducing excitation from cholinergic interneurons. Thus, we reveal the mechanisms of GABA-A receptor modulation of dopamine release and provide new insights into the actions of benzodiazepines within the striatum.
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Affiliation(s)
- Paul F Kramer
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Emily L Twedell
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Jung Hoon Shin
- Laboratory on Neurobiology of Compulsive Behaviors, National Institute of Alcohol Abuse and Alcoholism, National Institutes of HealthBethesdaUnited States
| | - Renshu Zhang
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
| | - Zayd M Khaliq
- Cellular Neurophysiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesdaUnited States
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4
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Tonic GABA A Conductance Favors Spike-Timing-Dependent over Theta-Burst-Induced Long-Term Potentiation in the Hippocampus. J Neurosci 2020; 40:4266-4276. [PMID: 32327534 DOI: 10.1523/jneurosci.2118-19.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 03/21/2020] [Accepted: 04/15/2020] [Indexed: 11/21/2022] Open
Abstract
Synaptic plasticity is triggered by different patterns of network activity. Here, we investigated how LTP in CA3-CA1 synapses induced by different stimulation patterns is affected by tonic GABAA conductances in rat hippocampal slices. Spike-timing-dependent LTP was induced by pairing Schaffer collateral stimulation with antidromic stimulation of CA1 pyramidal neurons. Theta-burst-induced LTP was induced by theta-burst stimulation of Schaffer collaterals. We mimicked increased tonic GABAA conductance by bath application of 30 μm GABA. Surprisingly, tonic GABAA conductance selectively suppressed theta-burst-induced LTP but not spike-timing-dependent LTP. We combined whole-cell patch-clamp electrophysiology, two-photon Ca2+ imaging, glutamate uncaging, and mathematical modeling to dissect the mechanisms underlying these differential effects of tonic GABAA conductance. We found that Ca2+ transients during pairing of an action potential with an EPSP were less sensitive to tonic GABAA conductance-induced shunting inhibition than Ca2+ transients induced by EPSP burst. Our results may explain how different forms of memory are affected by increasing tonic GABAA conductances under physiological or pathologic conditions, as well as under the influence of substances that target extrasynaptic GABAA receptors (e.g., neurosteroids, sedatives, antiepileptic drugs, and alcohol).SIGNIFICANCE STATEMENT Brain activity is associated with neuronal firing and synaptic signaling among neurons. Synaptic plasticity represents a mechanism for learning and memory. However, some neurotransmitters that escape the synaptic cleft or are released by astrocytes can target extrasynaptic receptors. Extrasynaptic GABAA receptors mediate tonic conductances that reduce the excitability of neurons by shunting. This results in the decreased ability for neurons to fire action potentials, but when action potentials are successfully triggered, tonic conductances are unable to reduce them significantly. As such, tonic GABAA conductances have minimal effects on spike-timing-dependent synaptic plasticity while strongly attenuating the plasticity evoked by EPSP bursts. Our findings shed light on how changes in tonic conductances can selectively affect different forms of learning and memory.
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5
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Dynamical mechanism for conduction failure behavior of action potentials related to pain information transmission. Neurocomputing 2020. [DOI: 10.1016/j.neucom.2019.12.114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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6
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Traub RD, Whittington MA, Maier N, Schmitz D, Nagy JI. Could electrical coupling contribute to the formation of cell assemblies? Rev Neurosci 2019; 31:121-141. [DOI: 10.1515/revneuro-2019-0059] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/07/2019] [Indexed: 12/20/2022]
Abstract
Abstract
Cell assemblies and central pattern generators (CPGs) are related types of neuronal networks: both consist of interacting groups of neurons whose collective activities lead to defined functional outputs. In the case of a cell assembly, the functional output may be interpreted as a representation of something in the world, external or internal; for a CPG, the output ‘drives’ an observable (i.e. motor) behavior. Electrical coupling, via gap junctions, is critical for the development of CPGs, as well as for their actual operation in the adult animal. Electrical coupling is also known to be important in the development of hippocampal and neocortical principal cell networks. We here argue that electrical coupling – in addition to chemical synapses – may therefore contribute to the formation of at least some cell assemblies in adult animals.
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Affiliation(s)
- Roger D. Traub
- AI Foundations, IBM T.J. Watson Research Center , Yorktown Heights, NY 10598 , USA
| | | | - Nikolaus Maier
- Charité-Universitätsmedizin Berlin , Neuroscience Research Center , Charitéplatz 1 , D-10117 Berlin , Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin , Neuroscience Research Center , Charitéplatz 1 , D-10117 Berlin , Germany
| | - James I. Nagy
- Department of Physiology and Pathophysiology , University of Manitoba , Winnipeg R3E OJ9, MB , Canada
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7
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Kawaguchi SY. Dynamic Factors for Transmitter Release at Small Presynaptic Boutons Revealed by Direct Patch-Clamp Recordings. Front Cell Neurosci 2019; 13:269. [PMID: 31249514 PMCID: PMC6582627 DOI: 10.3389/fncel.2019.00269] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/29/2019] [Indexed: 12/29/2022] Open
Abstract
Small size of an axon and presynaptic structures have hindered direct functional analysis of axonal signaling and transmitter release at presynaptic boutons in the central nervous system. However, recent technical advances in subcellular patch-clamp recordings and in fluorescent imagings are shedding light on the dynamic nature of axonal and presynaptic mechanisms. Here I summarize the functional design of an axon and presynaptic boutons, such as diversity and activity-dependent changes of action potential (AP) waveforms, Ca2+ influx, and kinetics of transmitter release, revealed by the technical tour de force of direct patch-clamp recordings and the leading-edge fluorescent imagings. I highlight the critical factors for dynamic modulation of transmitter release and presynaptic short-term plasticity.
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Affiliation(s)
- Shin-Ya Kawaguchi
- Society-Academia Collaboration for Innovation, Kyoto University, Kyoto, Japan.,Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan.,Institute for Advanced Study, Kyoto University, Kyoto, Japan
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8
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Jin X, Chen Q, Song Y, Zheng J, Xiao K, Shao S, Fu Z, Yi M, Yang Y, Huang Z. Dopamine D2 receptors regulate the action potential threshold by modulating T‐type calcium channels in stellate cells of the medial entorhinal cortex. J Physiol 2019; 597:3363-3387. [PMID: 31049961 DOI: 10.1113/jp277976] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 04/24/2019] [Indexed: 11/08/2022] Open
Affiliation(s)
- Xueqin Jin
- State Key Laboratory of Natural and Biomimetic DrugsDepartment of Molecular and Cellular PharmacologySchool of Pharmaceutical SciencesPeking University Health Science Centre Beijing 100191 China
| | - Qian Chen
- State Key Laboratory of Natural and Biomimetic DrugsDepartment of Molecular and Cellular PharmacologySchool of Pharmaceutical SciencesPeking University Health Science Centre Beijing 100191 China
| | - Yan Song
- State Key Laboratory of Natural and Biomimetic DrugsDepartment of Molecular and Cellular PharmacologySchool of Pharmaceutical SciencesPeking University Health Science Centre Beijing 100191 China
| | - Jie Zheng
- Neuroscience Research InstitutePeking University Health Science Center Beijing 100191 China
| | - Kuo Xiao
- State Key Laboratory of Natural and Biomimetic DrugsDepartment of Molecular and Cellular PharmacologySchool of Pharmaceutical SciencesPeking University Health Science Centre Beijing 100191 China
| | - Shan Shao
- Neuroscience Research InstitutePeking University Health Science Center Beijing 100191 China
| | - Zibing Fu
- Neuroscience Research InstitutePeking University Health Science Center Beijing 100191 China
| | - Ming Yi
- Neuroscience Research InstitutePeking University Health Science Center Beijing 100191 China
- Key Laboratory for NeuroscienceMinistry of Education/National Health and Family Planning CommissionPeking University Beijing 100191 China
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular PharmacologyCollege of Pharmacy, Purdue University West Lafayette IN 47907 USA
- Purdue Institute for Integrative Neuroscience 575 Stadium Mall Drive West Lafayette IN 47907 USA
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic DrugsDepartment of Molecular and Cellular PharmacologySchool of Pharmaceutical SciencesPeking University Health Science Centre Beijing 100191 China
- Key Laboratory for NeuroscienceMinistry of Education/National Health and Family Planning CommissionPeking University Beijing 100191 China
- Department of Molecular and Cellular PharmacologyPeking University Health Science Center 38 Xue Yuan Road Beijing 100191 China
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9
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Zbili M, Debanne D. Past and Future of Analog-Digital Modulation of Synaptic Transmission. Front Cell Neurosci 2019; 13:160. [PMID: 31105529 PMCID: PMC6492051 DOI: 10.3389/fncel.2019.00160] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/08/2019] [Indexed: 01/12/2023] Open
Abstract
Action potentials (APs) are generally produced in response to complex summation of excitatory and inhibitory synaptic inputs. While it is usually considered as a digital event, both the amplitude and width of the AP are significantly impacted by the context of its emission. In particular, the analog variations in subthreshold membrane potential determine the spike waveform and subsequently affect synaptic strength, leading to the so-called analog-digital modulation of synaptic transmission. We review here the numerous evidence suggesting context-dependent modulation of spike waveform, the discovery analog-digital modulation of synaptic transmission in invertebrates and its recent validation in mammals. We discuss the potential roles of analog-digital transmission in the physiology of neural networks.
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Affiliation(s)
- Mickael Zbili
- UNIS, UMR 1072, INSERM AMU, Marseille, France.,CRNL, INSERM U1028-CNRS UMR5292-Université Claude Bernard Lyon1, Lyon, France
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10
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Burke KJ, Keeshen CM, Bender KJ. Two Forms of Synaptic Depression Produced by Differential Neuromodulation of Presynaptic Calcium Channels. Neuron 2018; 99:969-984.e7. [PMID: 30122380 PMCID: PMC7874512 DOI: 10.1016/j.neuron.2018.07.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/03/2018] [Accepted: 07/18/2018] [Indexed: 01/09/2023]
Abstract
Neuromodulators are important regulators of synaptic transmission throughout the brain. At the presynaptic terminal, neuromodulation of calcium channels (CaVs) can affect transmission not only by changing neurotransmitter release probability, but also by shaping short-term plasticity (STP). Indeed, changes in STP are often considered a requirement for defining a presynaptic site of action. Nevertheless, some synapses exhibit non-canonical forms of neuromodulation, where release probability is altered without a corresponding change in STP. Here, we identify biophysical mechanisms whereby both canonical and non-canonical presynaptic neuromodulation can occur at the same synapse. At a subset of glutamatergic terminals in prefrontal cortex, GABAB and D1/D5 dopamine receptors suppress release probability with and without canonical increases in short-term facilitation by modulating different aspects of presynaptic CaV function. These findings establish a framework whereby signaling from multiple neuromodulators can converge on presynaptic CaVs to differentially tune release dynamics at the same synapse.
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Affiliation(s)
- Kenneth J Burke
- Neuroscience Graduate Program, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Caroline M Keeshen
- Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Kevin J Bender
- Neuroscience Graduate Program, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA; Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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11
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Jiang Y, Xiao Y, Zhang X, Shu Y. Activation of axon initial segmental GABA A receptors inhibits action potential generation in neocortical GABAergic interneurons. Neuropharmacology 2018; 138:97-105. [PMID: 29883765 DOI: 10.1016/j.neuropharm.2018.05.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 05/14/2018] [Accepted: 05/20/2018] [Indexed: 10/16/2022]
Abstract
Ionotropic GABAA receptors expressing at the axon initial segment (AIS) of glutamatergic pyramidal cell (PC) in the cortex plays critical roles in regulating action potential generation. However, it remains unclear whether these receptors also express at the AIS of cortical GABAergic interneurons. In mouse prefrontal cortical slices, we performed experiments at the soma and AIS of the two most abundant GABAergic interneurons: parvalbumin (PV) and somatostatin (SST) positive neurons. Local application of GABA at the perisomatic axonal regions could evoke picrotoxin-sensitive currents with a reversal potential near the Cl- equilibrium potential. Puffing agonists to outside-out patches excised from AIS confirmed the expression of GABAA receptors. Further pharmacological experiments revealed that GABAA receptors in AIS of PV neurons contain α1 subunits, different from those containing α2/3 in AIS and α4 in axon trunk of layer-5 PCs. Cell-attached recording at the soma of PV and SST neurons revealed that the activation of AIS GABAA receptors inhibits the action potential generation induced by synaptic stimulation. Together, our results demonstrate that the AIS of PV and SST neurons express GABAA receptors with distinct subunit composition, which exert an inhibitory effect on neuronal excitability in these inhibitory interneurons.
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Affiliation(s)
- Yanbo Jiang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Yujie Xiao
- State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiaoxue Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University, Beijing 100875, China
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning, IDG/McGovern Institute for Brain Research, School of Brain and Cognitive Sciences, Beijing Normal University, Beijing 100875, China.
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12
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Abstract
Axons link distant brain regions and are usually considered as simple transmission cables in which reliable propagation occurs once an action potential has been generated. Safe propagation of action potentials relies on specific ion channel expression at strategic points of the axon such as nodes of Ranvier or axonal branch points. However, while action potentials are generally considered as the quantum of neuronal information, their signaling is not entirely digital. In fact, both their shape and their conduction speed have been shown to be modulated by activity, leading to regulations of synaptic latency and synaptic strength. We report here newly identified mechanisms of (1) safe spike propagation along the axon, (2) compartmentalization of action potential shape in the axon, (3) analog modulation of spike-evoked synaptic transmission and (4) alteration in conduction time after persistent regulation of axon morphology in central neurons. We discuss the contribution of these regulations in information processing.
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Affiliation(s)
- Sylvain Rama
- UNIS, UMR_S 1072, INSERM, Aix-Marseille Université, 13015 Marseille, France; Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Mickaël Zbili
- UNIS, UMR_S 1072, INSERM, Aix-Marseille Université, 13015 Marseille, France
| | - Dominique Debanne
- UNIS, UMR_S 1072, INSERM, Aix-Marseille Université, 13015 Marseille, France.
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13
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Neuroanatomical alterations and synaptic plasticity impairment in the perirhinal cortex of the Ts65Dn mouse model of Down syndrome. Neurobiol Dis 2017; 106:89-100. [DOI: 10.1016/j.nbd.2017.06.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 11/23/2022] Open
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14
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Jiang L, Ni H, Wang QY, Huang L, Zhao SD, Yu JD, Ge RJ. Dual face of axonal inhibitory inputs in the modulation of neuronal excitability in cortical pyramidal neurons. Neural Regen Res 2017; 12:1079-1085. [PMID: 28852389 PMCID: PMC5558486 DOI: 10.4103/1673-5374.211186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Limited by the tiny structure of axons, the effects of these axonal hyperpolarizing inputs on neuronal activity have not been directly elucidated. Here, we imitated these processes by simultaneously recording the activities of the somas and proximal axons of cortical pyramidal neurons. We found that spikes and subthreshold potentials propagate between somas and axons with high fidelity. Furthermore, inhibitory inputs on axons have opposite effects on neuronal activity according to their temporal integration with upstream signals. Concurrent with somatic depolarization, inhibitory inputs on axons decrease neuronal excitability and impede spike generation. In addition, following action potentials, inhibitory inputs on an axon increase neuronal spike capacity and improve spike precision. These results indicate that inhibitory inputs on proximal axons have dual regulatory functions in neuronal activity (suppression or facilitation) according to neuronal network patterns.
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Affiliation(s)
- Lei Jiang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China.,Department of General Surgery, The Second Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui Province, China
| | - Hong Ni
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Qi-Yi Wang
- Department of Physiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Li Huang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Shi-di Zhao
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
| | - Jian-Dong Yu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Joint International Research Laboratory of CNS Regeneration, Ministry of Education, Jinan University, Guangzhou, Guangdong Province, China
| | - Rong-Jing Ge
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui Province, China
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15
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Barry JM. Axonal activity in vivo: technical considerations and implications for the exploration of neural circuits in freely moving animals. Front Neurosci 2015; 9:153. [PMID: 25999806 PMCID: PMC4422007 DOI: 10.3389/fnins.2015.00153] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 04/15/2015] [Indexed: 11/13/2022] Open
Abstract
While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We have recently reported extracellular tetrode recordings of short duration waveforms (SDWs) with an average peak-trough duration less than 172 μs. These waveforms have significantly shorter duration than somatic action potentials and tend to be triphasic. The present review discusses further data that suggests SDWs are representative of axonal activity, how this characterization allows for more accurate classification of somatic activity and could serve as a means of exploring signal integration in neural circuits. The review also discusses how axons may function as more than neural cables and the implications this may have for axonal information processing. While the technical challenges necessary for the exploration of axonal processes in functional neural circuits during behavior are impressive, preliminary evidence suggests that the in vivo study of axons is attainable. The resulting theoretical implications for systems level function make refinement of this approach a necessary goal toward developing a more complete understanding of the processes underlying learning, memory and attention as well as the pathological states underlying mental illness and epilepsy.
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Affiliation(s)
- Jeremy M Barry
- Department of Neurology, Geisel School of Medicine at Dartmouth Lebanon, NH, USA ; Epilepsy, Development and Cognition Group at UVM, Department of Neurological Sciences, University of Vermont Burlington, VT, USA
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