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Papazoglou A, Arshaad MI, Henseler C, Daubner J, Broich K, Hescheler J, Ehninger D, Haenisch B, Weiergräber M. Ca v3 T-Type Voltage-Gated Ca 2+ Channels and the Amyloidogenic Environment: Pathophysiology and Implications on Pharmacotherapy and Pharmacovigilance. Int J Mol Sci 2022; 23:3457. [PMID: 35408817 PMCID: PMC8998330 DOI: 10.3390/ijms23073457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 12/07/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) were reported to play a crucial role in neurotransmitter release, dendritic resonance phenomena and integration, and the regulation of gene expression. In the septohippocampal system, high- and low-voltage-activated (HVA, LVA) Ca2+ channels were shown to be involved in theta genesis, learning, and memory processes. In particular, HVA Cav2.3 R-type and LVA Cav3 T-type Ca2+ channels are expressed in the medial septum-diagonal band of Broca (MS-DBB), hippocampal interneurons, and pyramidal cells, and ablation of both channels was proven to severely modulate theta activity. Importantly, Cav3 Ca2+ channels contribute to rebound burst firing in septal interneurons. Consequently, functional impairment of T-type Ca2+ channels, e.g., in null mutant mouse models, caused tonic disinhibition of the septohippocampal pathway and subsequent enhancement of hippocampal theta activity. In addition, impairment of GABA A/B receptor transcription, trafficking, and membrane translocation was observed within the septohippocampal system. Given the recent findings that amyloid precursor protein (APP) forms complexes with GABA B receptors (GBRs), it is hypothesized that T-type Ca2+ current reduction, decrease in GABA receptors, and APP destabilization generate complex functional interdependence that can constitute a sophisticated proamyloidogenic environment, which could be of potential relevance in the etiopathogenesis of Alzheimer's disease (AD). The age-related downregulation of T-type Ca2+ channels in humans goes together with increased Aβ levels that could further inhibit T-type channels and aggravate the proamyloidogenic environment. The mechanistic model presented here sheds new light on recent reports about the potential risks of T-type Ca2+ channel blockers (CCBs) in dementia, as observed upon antiepileptic drug application in the elderly.
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Affiliation(s)
- Anna Papazoglou
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Muhammad Imran Arshaad
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Christina Henseler
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Johanna Daubner
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Karl Broich
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
| | - Jürgen Hescheler
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Dan Ehninger
- Translational Biogerontology, German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany;
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
| | - Britta Haenisch
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
- Center for Translational Medicine, Medical Faculty, University of Bonn, 53113 Bonn, Germany
| | - Marco Weiergräber
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
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Jenks KR, Tsimring K, Ip JPK, Zepeda JC, Sur M. Heterosynaptic Plasticity and the Experience-Dependent Refinement of Developing Neuronal Circuits. Front Neural Circuits 2021; 15:803401. [PMID: 34949992 PMCID: PMC8689143 DOI: 10.3389/fncir.2021.803401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/15/2021] [Indexed: 01/01/2023] Open
Abstract
Neurons remodel the structure and strength of their synapses during critical periods of development in order to optimize both perception and cognition. Many of these developmental synaptic changes are thought to occur through synapse-specific homosynaptic forms of experience-dependent plasticity. However, homosynaptic plasticity can also induce or contribute to the plasticity of neighboring synapses through heterosynaptic interactions. Decades of research in vitro have uncovered many of the molecular mechanisms of heterosynaptic plasticity that mediate local compensation for homosynaptic plasticity, facilitation of further bouts of plasticity in nearby synapses, and cooperative induction of plasticity by neighboring synapses acting in concert. These discoveries greatly benefited from new tools and technologies that permitted single synapse imaging and manipulation of structure, function, and protein dynamics in living neurons. With the recent advent and application of similar tools for in vivo research, it is now feasible to explore how heterosynaptic plasticity contribute to critical periods and the development of neuronal circuits. In this review, we will first define the forms heterosynaptic plasticity can take and describe our current understanding of their molecular mechanisms. Then, we will outline how heterosynaptic plasticity may lead to meaningful refinement of neuronal responses and observations that suggest such mechanisms are indeed at work in vivo. Finally, we will use a well-studied model of cortical plasticity—ocular dominance plasticity during a critical period of visual cortex development—to highlight the molecular overlap between heterosynaptic and developmental forms of plasticity, and suggest potential avenues of future research.
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Affiliation(s)
- Kyle R Jenks
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Katya Tsimring
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jacque Pak Kan Ip
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jose C Zepeda
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mriganka Sur
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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Kourosh-Arami M, Hosseini N, Komaki A. Brain is modulated by neuronal plasticity during postnatal development. J Physiol Sci 2021; 71:34. [PMID: 34789147 PMCID: PMC10716960 DOI: 10.1186/s12576-021-00819-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 10/27/2021] [Indexed: 11/10/2022]
Abstract
Neuroplasticity is referred to the ability of the nervous system to change its structure or functions as a result of former stimuli. It is a plausible mechanism underlying a dynamic brain through adaptation processes of neural structure and activity patterns. Nevertheless, it is still unclear how the plastic neural systems achieve and maintain their equilibrium. Additionally, the alterations of balanced brain dynamics under different plasticity rules have not been explored either. Therefore, the present article primarily aims to review recent research studies regarding homosynaptic and heterosynaptic neuroplasticity characterized by the manipulation of excitatory and inhibitory synaptic inputs. Moreover, it attempts to understand different mechanisms related to the main forms of synaptic plasticity at the excitatory and inhibitory synapses during the brain development processes. Hence, this study comprised surveying those articles published since 1988 and available through PubMed, Google Scholar and science direct databases on a keyword-based search paradigm. All in all, the study results presented extensive and corroborative pieces of evidence for the main types of plasticity, including the long-term potentiation (LTP) and long-term depression (LTD) of the excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs).
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Affiliation(s)
- Masoumeh Kourosh-Arami
- Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Nasrin Hosseini
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
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Arshaad MI, Siwek ME, Henseler C, Daubner J, Ehninger D, Hescheler J, Sachinidis A, Broich K, Papazoglou A, Weiergräber M. Enhanced hippocampal type II theta activity AND altered theta architecture in mice lacking the Ca v3.2 T-type voltage-gated calcium channel. Sci Rep 2021; 11:1099. [PMID: 33441788 PMCID: PMC7806756 DOI: 10.1038/s41598-020-79763-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 12/08/2020] [Indexed: 12/20/2022] Open
Abstract
T-type Ca2+ channels are assumed to contribute to hippocampal theta oscillations. We used implantable video-EEG radiotelemetry and qPCR to unravel the role of Cav3.2 Ca2+ channels in hippocampal theta genesis. Frequency analysis of spontaneous long-term recordings in controls and Cav3.2-/- mice revealed robust increase in relative power in the theta (4-8 Hz) and theta-alpha (4-12 Hz) ranges, which was most prominent during the inactive stages of the dark cycles. Urethane injection experiments also showed enhanced type II theta activity and altered theta architecture following Cav3.2 ablation. Next, gene candidates from hippocampal transcriptome analysis of control and Cav3.2-/- mice were evaluated using qPCR. Dynein light chain Tctex-Type 1 (Dynlt1b) was significantly reduced in Cav3.2-/- mice. Furthermore, a significant reduction of GABA A receptor δ subunits and GABA B1 receptor subunits was observed in the septohippocampal GABAergic system. Our results demonstrate that ablation of Cav3.2 significantly alters type II theta activity and theta architecture. Transcriptional changes in synaptic transporter proteins and GABA receptors might be functionally linked to the electrophysiological phenotype.
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Affiliation(s)
- Muhammad Imran Arshaad
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Magdalena Elisabeth Siwek
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Christina Henseler
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Johanna Daubner
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Dan Ehninger
- Molecular and Cellular Cognition, German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Sigmund-Freud-Str. 27, 53127, Bonn, Germany
| | - Jürgen Hescheler
- Institute of Neurophysiology, University of Cologne, Faculty of Medicine, Robert-Koch-Str. 39, 50931, Cologne, Germany
| | - Agapios Sachinidis
- Institute of Neurophysiology, University of Cologne, Faculty of Medicine, Robert-Koch-Str. 39, 50931, Cologne, Germany
| | - Karl Broich
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Anna Papazoglou
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany
| | - Marco Weiergräber
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175, Bonn, Germany.
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Miao QL, Herlitze S, Mark MD, Noebels JL. Adult loss of Cacna1a in mice recapitulates childhood absence epilepsy by distinct thalamic bursting mechanisms. Brain 2020; 143:161-174. [PMID: 31800012 PMCID: PMC6935748 DOI: 10.1093/brain/awz365] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/09/2019] [Accepted: 09/29/2019] [Indexed: 12/15/2022] Open
Abstract
Inborn errors of CACNA1A-encoded P/Q-type calcium channels impair synaptic transmission, producing early and lifelong neurological deficits, including childhood absence epilepsy, ataxia and dystonia. Whether these impairments owe their pathologies to defective channel function during the critical period for thalamic network stabilization in immature brain remains unclear. Here we show that mice with tamoxifen-induced adult-onset ablation of P/Q channel alpha subunit (iKOp/q) display identical patterns of dysfunction, replicating the inborn loss-of-function phenotypes and, therefore demonstrate that these neurological defects do not rely upon developmental abnormality. Unexpectedly, unlike the inborn model, the adult-onset pattern of excitability changes believed to be pathogenic within the thalamic network is non-canonical. Specifically, adult ablation of P/Q channels does not promote Cacna1g-mediated burst firing or T-type calcium current (IT) in the thalamocortical relay neurons; however, burst firing in thalamocortical relay neurons remains essential as iKOp/q mice generated on a Cacna1g deleted background show substantially diminished seizure generation. Moreover, in thalamic reticular nucleus neurons, burst firing is impaired accompanied by attenuated IT. Interestingly, inborn deletion of thalamic reticular nucleus-enriched, human childhood absence epilepsy-linked gene Cacna1h in iKOp/q mice reduces thalamic reticular nucleus burst firing and promotes rather than reduces seizure, indicating an epileptogenic role for loss-of-function Cacna1h gene variants reported in human childhood absence epilepsy cases. Together, our results demonstrate that P/Q channels remain critical for maintaining normal thalamocortical oscillations and motor control in the adult brain, and suggest that the developmental plasticity of membrane currents regulating pathological rhythmicity is both degenerate and age-dependent.
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Affiliation(s)
- Qing-Long Miao
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston TX, USA
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, Ruhr University of Bochum, Bochum, Germany
| | - Melanie D Mark
- Department of Zoology and Neurobiology, Ruhr University of Bochum, Bochum, Germany
| | - Jeffrey L Noebels
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston TX, USA
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Lah MHC, Reza F, Begum T, Abdullah JM. Role of Pre-Synaptic NMDA Receptors in the Modulation of Inhibitory Synaptic Transmission in Sensory-Motor and Visual Cortical Pyramidal Neurons in Brain Slices of Young Epileptic Mice. Malays J Med Sci 2019; 25:27-39. [PMID: 30899185 PMCID: PMC6422549 DOI: 10.21315/mjms2018.25.3.4] [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: 02/12/2018] [Accepted: 04/24/2018] [Indexed: 10/28/2022] Open
Abstract
Background Previous studies from animal models have shown that pre-synaptic NMDA receptors (preNMDARs) are present in the cortex, but the role of inhibition mediated by preNMDARs during epileptogenesis remains unclear. In this study, we wanted to observe the changes in GABAergic inhibition through preNMDARs in sensory-motor and visual cortical pyramidal neurons after pilocarpine-induced status epilepticus. Methods Using a pilocarpine-induced epileptic mouse model, sensory-motor and visual cortical slices were prepared, and the whole-cell patch clamp technique was used to record spontaneous inhibitory post-synaptic currents (sIPSCs). Results The primary finding was that the mean amplitude of sIPSC from the sensory-motor cortex increased significantly in epileptic mice when the recording pipette contained MK-801 compared to control mice, whereas the mean sIPSC frequency was not significantly different, indicating that post-synaptic mechanisms are involved. However, there was no significant pre-synaptic inhibition through preNMDARs in the acute brain slices from pilocarpine-induced epileptic mice. Conclusion In the acute case of epilepsy, a compensatory mechanism of post-synaptic inhibition, possibly from ambient GABA, was observed through changes in the amplitude without significant changes in the frequency of sIPSC compared to control mice. The role of preNMDAR-mediated inhibition in epileptogenesis during the chronic condition or in the juvenile stage warrants further investigation.
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Affiliation(s)
- Muhammad Hanif Che Lah
- Department of Neurosciences, School of Medical Sciences, Universiti Sains, Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Faruque Reza
- Department of Neurosciences, School of Medical Sciences, Universiti Sains, Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Tahamina Begum
- Department of Neurosciences, School of Medical Sciences, Universiti Sains, Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Jafri Malin Abdullah
- Department of Neurosciences, School of Medical Sciences, Universiti Sains, Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia.,Center for Neuroscience Services and Research (P3Neuro), Universiti Sains, Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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Joksimovic SM, Eggan P, Izumi Y, Joksimovic SL, Tesic V, Dietz RM, Orfila JE, DiGruccio MR, Herson PS, Jevtovic-Todorovic V, Zorumski CF, Todorovic SM. The role of T-type calcium channels in the subiculum: to burst or not to burst? J Physiol 2017; 595:6327-6348. [PMID: 28744923 PMCID: PMC5621493 DOI: 10.1113/jp274565] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 07/07/2017] [Indexed: 01/16/2023] Open
Abstract
KEY POINTS Pharmacological, molecular and genetic data indicate a prominent role of low-voltage-activated T-type calcium channels (T-channels) in the firing activity of both pyramidal and inhibitory interneurons in the subiculum. Pharmacological inhibition of T-channels switched burst firing with lower depolarizing stimuli to regular spiking, and fully abolished hyperpolarization-induced burst firing. Our molecular studies showed that CaV 3.1 is the most abundantly expressed isoform of T-channels in the rat subiculum. Consistent with this finding, both regular-spiking and burst firing patterns were profoundly depressed in the mouse with global deletion of CaV 3.1 isoform of T-channels. Selective inhibition of T-channels and global deletion of CaV 3.1 channels completely suppressed development of long-term potentiation (LTP) in the CA1-subiculum, but not in the CA3-CA1 pathway. ABSTRACT Several studies suggest that voltage-gated calcium currents are involved in generating high frequency burst firing in the subiculum, but the exact nature of these currents remains unknown. Here, we used selective pharmacology, molecular and genetic approaches to implicate Cav3.1-containing T-channels in subicular burst firing, in contrast to several previous reports discounting T-channels as major contributors to subicular neuron physiology. Furthermore, pharmacological antagonism of T-channels, as well as global deletion of CaV3.1 isoform, completely suppressed development of long-term potentiation (LTP) in the CA1-subiculum, but not in the CA3-CA1 pathway. Our results indicate that excitability and synaptic plasticity of subicular neurons relies heavily on T-channels. Hence, T-channels may be a promising new drug target for different cognitive deficits.
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Affiliation(s)
- Srdjan M Joksimovic
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Pierce Eggan
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Yukitoshi Izumi
- Department of Psychiatry & Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Sonja Lj Joksimovic
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Vesna Tesic
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Robert M Dietz
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - James E Orfila
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Michael R DiGruccio
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, CA, 95616, USA
| | - Paco S Herson
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
| | - Charles F Zorumski
- Department of Psychiatry & Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Colorado, School of Medicine, Aurora, CO, 80045, USA
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8
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Sugimura T, Yamamoto M, Yamada K, Komatsu Y, Yoshimura Y. Visual experience regulates the development of long-term synaptic modifications induced by low-frequency stimulation in mouse visual cortex. Neurosci Res 2017; 120:36-44. [PMID: 28284708 DOI: 10.1016/j.neures.2017.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 02/22/2017] [Accepted: 02/23/2017] [Indexed: 10/20/2022]
Abstract
Manipulation of visual experience can considerably modify visual responses of visual cortical neurons even in adulthood in the mouse, although the modification is less profound than that observed during the critical period. Our previous studies demonstrated that low-frequency (2Hz) stimulation for 15min applied to layer 4 induces T-type Ca2+ channel-dependent long-term potentiation (LTP) at excitatory synapses in layer 2/3 neurons of visual cortex during the critical period. In this study, we investigated whether low-frequency stimulation could induce synaptic plasticity in adult mice. We found that 2Hz stimulation induced LTP of extracellular field potentials evoked by stimulation of layer 4 in layer 2/3 in adulthood as during the critical period. LTP in adulthood was blocked by L-type, but not T-type, Ca2+ channel antagonists, whereas LTP during the critical period was blocked by T-type, but not L-type, Ca2+ channel antagonists. This developmental change in LTP was prevented by dark rearing. Under pharmacological blockade of GABAA receptors, T-type Ca2+ channel-dependent LTP occurred, whereas L-type Ca2+ channel-dependent LTP did not occur. These results suggest that different forms of synaptic plasticity can contribute separately to experience-dependent modification of visual responses during the critical period and in adulthood.
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Affiliation(s)
- Taketoshi Sugimura
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan; Department of Neurophysiology, Nara Medical University, Kashihara 634-8521, Japan
| | - Mariko Yamamoto
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan
| | - Kazumasa Yamada
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Division of Physical Therapy, Faculty of Rehabilitation and Care, Seijoh University, Tokai 476-8588, Japan
| | - Yukio Komatsu
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
| | - Yumiko Yoshimura
- Division of Visual Information Processing, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
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9
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Abstract
The role of T-type calcium currents is rarely considered in the extensive literature covering the mechanisms of long-term synaptic plasticity. This situation reflects the lack of suitable T-type channel antagonists that till recently has hampered investigations of the functional roles of these channels. However, with the development of new pharmacological and genetic tools, a clear involvement of T-type channels in synaptic plasticity is starting to emerge. Here, we review a number of studies showing that T-type channels participate to numerous homo- and hetero-synaptic plasticity mechanisms that involve different molecular partners and both pre- and post-synaptic modifications. The existence of T-channel dependent and independent plasticity at the same synapse strongly suggests a subcellular localization of these channels and their partners that allows specific interactions. Moreover, we illustrate the functional importance of T-channel dependent synaptic plasticity in neocortex and thalamus.
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Affiliation(s)
- Nathalie Leresche
- a Sorbonne Universités, Université Pierre et Marie Curie (UPMC) UM119, CNRS UMR8246, INSERM U1130, Neuroscience Paris Seine (NPS) , Paris , France
| | - Régis C Lambert
- a Sorbonne Universités, Université Pierre et Marie Curie (UPMC) UM119, CNRS UMR8246, INSERM U1130, Neuroscience Paris Seine (NPS) , Paris , France
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10
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Takeda-Uchimura Y, Uchimura K, Sugimura T, Yanagawa Y, Kawasaki T, Komatsu Y, Kadomatsu K. Requirement of keratan sulfate proteoglycan phosphacan with a specific sulfation pattern for critical period plasticity in the visual cortex. Exp Neurol 2015; 274:145-55. [PMID: 26277687 DOI: 10.1016/j.expneurol.2015.08.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/16/2015] [Accepted: 08/06/2015] [Indexed: 01/23/2023]
Abstract
Proteoglycans play important roles in regulating the development and functions of the brain. They consist of a core protein and glycosaminoglycans, which are long sugar chains of repeating disaccharide units with sulfation. A recent study demonstrated that the sulfation pattern of chondroitin sulfate on proteoglycans contributes to regulation of the critical period of experience-dependent plasticity in the mouse visual cortex. In the present study, we investigated the role of keratan sulfate (KS), another glycosaminoglycan, in critical period plasticity in the mouse visual cortex. Immunohistochemical analyses demonstrated the presence of KS containing disaccharide units of N-acetylglucosamine (GlcNAc)-6-sulfate and nonsulfated galactose during the critical period, although KS containing disaccharide units of GlcNAc-6-sulfate and galactose-6-sulfate was already known to disappear before that period. The KS chains were distributed diffusely in the extracellular space and densely around the soma of a large population of excitatory and inhibitory neurons. Electron microscopic analysis revealed that the KS was localized within the perisynaptic spaces and dendrites but not in presynaptic sites. KS was mainly located on phosphacan. In mice deficient in GlcNAc-6-O-sulfotransferase 1, which is one of the enzymes necessary for the synthesis of KS chains, the expression of KS was one half that in wild-type mice. In the knockout mice, monocular deprivation during the critical period resulted in a depression of deprived-eye responses but failed to produce potentiation of nondeprived-eye responses. In addition, T-type Ca(2+) channel-dependent long-term potentiation (LTP), which occurs only during the critical period, was not observed. These results suggest that regulation by KS-phosphacan with a specific sulfation pattern is necessary for the generation of LTP and hence the potentiation of nondeprived-eye responses after monocular deprivation.
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Affiliation(s)
- Yoshiko Takeda-Uchimura
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan; Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Kenji Uchimura
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Taketoshi Sugimura
- Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Toshisuke Kawasaki
- Research Center for Glycobiotechnology, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu, Shiga 525-8577, Japan
| | - Yukio Komatsu
- Department of Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
| | - Kenji Kadomatsu
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
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11
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Sugimura T, Yoshimura Y, Komatsu Y. TNFα is required for the production of T-type Ca2+ channel-dependent long-term potentiation in visual cortex. Neurosci Res 2015; 96:37-44. [DOI: 10.1016/j.neures.2015.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 02/06/2015] [Accepted: 02/10/2015] [Indexed: 10/24/2022]
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12
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Horibe S, Tarusawa E, Komatsu Y, Yoshimura Y. Ni2+-sensitive T-type Ca2+ channel currents are regulated in parallel with synaptic and visual response plasticity in visual cortex. Neurosci Res 2014; 87:33-9. [DOI: 10.1016/j.neures.2014.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/01/2014] [Accepted: 07/02/2014] [Indexed: 11/30/2022]
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13
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Gangarossa G, Laffray S, Bourinet E, Valjent E. T-type calcium channel Cav3.2 deficient mice show elevated anxiety, impaired memory and reduced sensitivity to psychostimulants. Front Behav Neurosci 2014; 8:92. [PMID: 24672455 PMCID: PMC3957728 DOI: 10.3389/fnbeh.2014.00092] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/03/2014] [Indexed: 01/28/2023] Open
Abstract
The fine-tuning of neuronal excitability relies on a tight control of Ca2+ homeostasis. The low voltage-activated (LVA) T-type calcium channels (Cav3.1, Cav3.2 and Cav3.3 isoforms) play a critical role in regulating these processes. Despite their wide expression throughout the central nervous system, the implication of T-type Cav3.2 isoform in brain functions is still poorly characterized. Here, we investigate the effect of genetic ablation of this isoform in affective disorders, including anxiety, cognitive functions as well as sensitivity to drugs of abuse. Using a wide range of behavioral assays we show that genetic ablation of the cacna1h gene results in an anxiety-like phenotype, whereas novelty-induced locomotor activity is unaffected. Deletion of the T-type channel Cav3.2 also triggers impairment of hippocampus-dependent recognition memories. Acute and sensitized hyperlocomotion induced by d-amphetamine and cocaine are dramatically reduced in T-type Cav3.2 deficient mice. In addition, the administration of the T-type blocker TTA-A2 prevented the expression of locomotor sensitization observed in wildtype mice. In conclusion, our data reveal that physiological activity of this specific Ca2+ channel is required for affective and cognitive behaviors. Moreover, our work highlights the interest of T-type channel blockers as therapeutic strategies to reverse drug-associated alterations.
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Affiliation(s)
- Giuseppe Gangarossa
- Institut de Génomique Fonctionnelle, CNRS UMR-5203, Montpellier, France ; INSERM U661, Montpellier, France ; Universités de Montpellier 1 and 2 UMR-5203, Montpellier, France
| | - Sophie Laffray
- Institut de Génomique Fonctionnelle, CNRS UMR-5203, Montpellier, France ; INSERM U661, Montpellier, France ; Universités de Montpellier 1 and 2 UMR-5203, Montpellier, France ; Laboratories of Excellence, Ion Channel Science and Therapeutics, Institut de Génomique Fonctionnelle Montpellier, France
| | - Emmanuel Bourinet
- Institut de Génomique Fonctionnelle, CNRS UMR-5203, Montpellier, France ; INSERM U661, Montpellier, France ; Universités de Montpellier 1 and 2 UMR-5203, Montpellier, France ; Laboratories of Excellence, Ion Channel Science and Therapeutics, Institut de Génomique Fonctionnelle Montpellier, France
| | - Emmanuel Valjent
- Institut de Génomique Fonctionnelle, CNRS UMR-5203, Montpellier, France ; INSERM U661, Montpellier, France ; Universités de Montpellier 1 and 2 UMR-5203, Montpellier, France
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14
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Abstract
The broad connectivity of inhibitory interneurons and the capacity of inhibitory synapses to be plastic make them ideal regulators of the level of excitability of many neurons simultaneously. Whether inhibitory synaptic plasticity may also contribute to the selective regulation of single neurons and local microcircuits activity has not been investigated. Here we demonstrate that in rat primary visual cortex inhibitory synaptic plasticity is connection specific and depends on the activation of postsynaptic GABAB-Gi/o protein signaling. Through the activation of this intracellular signaling pathway, inhibitory plasticity can alter the state of a single postsynaptic neuron and directly affect the induction of plasticity at its glutamatergic inputs. This interaction is modulated by sensory experience. Our data demonstrate that in recurrent circuits, excitatory and inhibitory forms of synaptic plasticity are not integrated as independent events, but interact to cooperatively drive the activity-dependent rewiring of local microcircuits.
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15
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Klyubin I, Ondrejcak T, Hayes J, Cullen WK, Mably AJ, Walsh DM, Rowan MJ. Neurotransmitter receptor and time dependence of the synaptic plasticity disrupting actions of Alzheimer's disease Aβ in vivo. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130147. [PMID: 24298149 PMCID: PMC3843879 DOI: 10.1098/rstb.2013.0147] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many endogenous factors influence the time course and extent of the detrimental effects of amyloid β-protein (Aβ) on synaptic function. Here, we assessed the impact of varying endogenous glutamatergic and cholinergic transmission by pharmacological means on the disruption of plasticity at hippocampal CA3-to-CA1 synapses in the anaesthetized rat. NMDA receptors (NMDARs) are considered critical in mediating Aβ-induced inhibition of long-term potentiation (LTP). However, intracerebroventricular injection of Aβ1-42 inhibited not only NMDAR-dependent LTP but also voltage-activated Ca(2+)-dependent LTP induced by strong conditioning stimulation during NMDAR blockade. On the other hand, another form of NMDAR-independent synaptic plasticity, endogenous acetylcholine-induced muscarinic receptor-dependent long-term enhancement, was not hindered by Aβ1-42. Interestingly, augmenting endogenous acetylcholine activation of nicotinic receptors prior to the injection of Aβ1-42 prevented the inhibition of NMDAR-dependent LTP, whereas the same intervention when introduced after the infusion of Aβ was ineffective. We also examined the duration of action of Aβ, including water soluble Aβ from Alzheimer's disease (AD) brain. Remarkably, the inhibition of LTP induction caused by a single injection of sodium dodecyl sulfate-stable Aβ dimer-containing AD brain extract persisted for at least a week. These findings highlight the need to increase our understanding of non-NMDAR mechanisms and of developing novel means of overcoming, rather than just preventing, the deleterious synaptic actions of Aβ.
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Affiliation(s)
- Igor Klyubin
- Department of Pharmacology and Therapeutics, Institute of Neuroscience, Trinity College, Biotechnology Building, Dublin 2, Republic ofIreland
| | - Tomas Ondrejcak
- Department of Pharmacology and Therapeutics, Institute of Neuroscience, Trinity College, Biotechnology Building, Dublin 2, Republic ofIreland
| | - Jennifer Hayes
- Department of Pharmacology and Therapeutics, Institute of Neuroscience, Trinity College, Biotechnology Building, Dublin 2, Republic ofIreland
| | - William K. Cullen
- Department of Pharmacology and Therapeutics, Institute of Neuroscience, Trinity College, Biotechnology Building, Dublin 2, Republic ofIreland
| | - Alexandra J. Mably
- Laboratory for Neurodegenerative Research, Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Institute of Medicine, 77-Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Dominic M. Walsh
- Laboratory for Neurodegenerative Research, Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Institute of Medicine, 77-Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Michael J. Rowan
- Department of Pharmacology and Therapeutics, Institute of Neuroscience, Trinity College, Biotechnology Building, Dublin 2, Republic ofIreland
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16
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Gu Y, Arruda-Carvalho M, Wang J, Janoschka SR, Josselyn SA, Frankland PW, Ge S. Optical controlling reveals time-dependent roles for adult-born dentate granule cells. Nat Neurosci 2012; 15:1700-6. [PMID: 23143513 PMCID: PMC3509272 DOI: 10.1038/nn.3260] [Citation(s) in RCA: 311] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/15/2012] [Indexed: 12/11/2022]
Abstract
Accumulating evidence suggests that global depletion of adult hippocampal neurogenesis influences its function and the timing of the depletion impacts the deficits. However, behavioral roles of adult-born neurons during their establishment of projections to CA3 pyramidal neurons remain largely unknown. Here we combined retroviral and optogenetic approaches to birth-date and reversibly control a group of adult-born neurons in adult mice. We show that adult-born neurons form functional synapses on CA3 pyramidal neurons as early as 2 weeks after birth, and that this projection to the CA3 area becomes stable by 4 weeks in age. Newborn neurons at this age exhibit enhanced plasticity compared to other stages. Notably, we found that reversibly silencing this cohort of ~4 week-old cells after training, but not cells of other ages, substantially disrupted retrieval of hippocampal memory. Our results identify a restricted time window for adult-born neurons exhibiting an essential role in hippocampal memory retrieval.
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Affiliation(s)
- Yan Gu
- Department of Neurobiology and Behavior, SUNY at Stony Brook, Stony Brook, New York, USA
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17
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Hirayama T, Tarusawa E, Yoshimura Y, Galjart N, Yagi T. CTCF is required for neural development and stochastic expression of clustered Pcdh genes in neurons. Cell Rep 2012; 2:345-57. [PMID: 22854024 DOI: 10.1016/j.celrep.2012.06.014] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 06/13/2012] [Accepted: 06/15/2012] [Indexed: 12/17/2022] Open
Abstract
The CCCTC-binding factor (CTCF) is a key molecule for chromatin conformational changes that promote cellular diversity, but nothing is known about its role in neurons. Here, we produced mice with a conditional knockout (cKO) of CTCF in postmitotic projection neurons, mostly in the dorsal telencephalon. The CTCF-cKO mice exhibited postnatal growth retardation and abnormal behavior and had defects in functional somatosensory mapping in the brain. In terms of gene expression, 390 transcripts were expressed at significantly different levels between CTCF-deficient and control cortex and hippocampus. In particular, the levels of 53 isoforms of the clustered protocadherin (Pcdh) genes, which are stochastically expressed in each neuron, declined markedly. Each CTCF-deficient neuron showed defects in dendritic arborization and spine density during brain development. Their excitatory postsynaptic currents showed normal amplitude but occurred with low frequency. Our results indicate that CTCF regulates functional neural development and neuronal diversity by controlling clustered Pcdh expression.
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Affiliation(s)
- Teruyoshi Hirayama
- KOKORO-Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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18
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Moriguchi S, Shioda N, Yamamoto Y, Tagashira H, Fukunaga K. The T-type voltage-gated calcium channel as a molecular target of the novel cognitive enhancer ST101: enhancement of long-term potentiation and CaMKII autophosphorylation in rat cortical slices. J Neurochem 2012; 121:44-53. [DOI: 10.1111/j.1471-4159.2012.07667.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Miyata S, Komatsu Y, Yoshimura Y, Taya C, Kitagawa H. Persistent cortical plasticity by upregulation of chondroitin 6-sulfation. Nat Neurosci 2012; 15:414-22, S1-2. [PMID: 22246436 DOI: 10.1038/nn.3023] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/06/2011] [Indexed: 11/09/2022]
Abstract
Cortical plasticity is most evident during a critical period in early life, but the mechanisms that restrict plasticity after the critical period are poorly understood. We found that a developmental increase in the 4-sulfation/6-sulfation (4S/6S) ratio of chondroitin sulfate proteoglycans (CSPGs), which are components of the brain extracellular matrix, leads to the termination of the critical period for ocular dominance plasticity in the mouse visual cortex. Condensation of CSPGs into perineuronal nets that enwrapped synaptic contacts on parvalbumin-expressing interneurons was prevented by cell-autonomous overexpression of chondroitin 6-sulfation, which maintains a low 4S/6S ratio. Furthermore, the increase in the 4S/6S ratio was required for the accumulation of Otx2, a homeoprotein that activates the development of parvalbumin-expressing interneurons, and for functional maturation of the electrophysiological properties of these cells. Our results indicate that the critical period for cortical plasticity is regulated by the 4S/6S ratio of CSPGs, which determines the maturation of parvalbumin-expressing interneurons.
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Affiliation(s)
- Shinji Miyata
- Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe, Japan
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20
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Retrieval of context-associated memory is dependent on the Ca(v)3.2 T-type calcium channel. PLoS One 2012; 7:e29384. [PMID: 22235292 PMCID: PMC3250437 DOI: 10.1371/journal.pone.0029384] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 11/28/2011] [Indexed: 11/19/2022] Open
Abstract
Among all voltage-gated calcium channels, the T-type Ca2+ channels encoded by the Cav3.2 genes are highly expressed in the hippocampus, which is associated with contextual, temporal and spatial learning and memory. However, the specific involvement of the Cav3.2 T-type Ca2+ channel in these hippocampus-dependent types of learning and memory remains unclear. To investigate the functional role of this channel in learning and memory, we subjected Cav3.2 homozygous and heterozygous knockout mice and their wild-type littermates to hippocampus-dependent behavioral tasks, including trace fear conditioning, the Morris water-maze and passive avoidance. The Cav3.2 −/− mice performed normally in the Morris water-maze and auditory trace fear conditioning tasks but were impaired in the context-cued trace fear conditioning, step-down and step-through passive avoidance tasks. Furthermore, long-term potentiation (LTP) could be induced for 180 minutes in hippocampal slices of WTs and Cav3.2 +/− mice, whereas LTP persisted for only 120 minutes in Cav3.2 −/− mice. To determine whether the hippocampal formation is responsible for the impaired behavioral phenotypes, we next performed experiments to knock down local function of the Cav3.2 T-type Ca2+ channel in the hippocampus. Wild-type mice infused with mibefradil, a T-type channel blocker, exhibited similar behaviors as homozygous knockouts. Taken together, our results demonstrate that retrieval of context-associated memory is dependent on the Cav3.2 T-type Ca2+ channel.
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21
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The many forms and functions of long term plasticity at GABAergic synapses. Neural Plast 2011; 2011:254724. [PMID: 21789285 PMCID: PMC3140781 DOI: 10.1155/2011/254724] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 03/22/2011] [Accepted: 05/23/2011] [Indexed: 01/12/2023] Open
Abstract
On February 12th 1973, Bliss and Lomo submitted their findings on activity-dependent plasticity of glutamatergic synapses. After this groundbreaking discovery, long-term potentiation (LTP) and depression (LTD) gained center stage in the study of learning, memory, and experience-dependent refinement of neural circuits. While LTP and LTD are extensively studied and their relevance to brain function is widely accepted, new experimental and theoretical work recently demonstrates that brain development and function relies on additional forms of plasticity, some of which occur at nonglutamatergic synapses. The strength of GABAergic synapses is modulated by activity, and new functions for inhibitory synaptic plasticity are emerging. Together with excitatory neurons, inhibitory neurons shape the excitability and dynamic range of neural circuits. Thus, the understanding of inhibitory synaptic plasticity is crucial to fully comprehend the physiology of brain circuits. Here, I will review recent findings about plasticity at GABAergic synapses and discuss how it may contribute to circuit function.
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Synaptic plasticity controls sensory responses through frequency-dependent gamma oscillation resonance. PLoS Comput Biol 2010; 6. [PMID: 20838581 PMCID: PMC2936516 DOI: 10.1371/journal.pcbi.1000927] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 08/10/2010] [Indexed: 11/19/2022] Open
Abstract
Synchronized gamma frequency oscillations in neural networks are thought to be important to sensory information processing, and their effects have been intensively studied. Here we describe a mechanism by which the nervous system can readily control gamma oscillation effects, depending selectively on visual stimuli. Using a model neural network simulation, we found that sensory response in the primary visual cortex is significantly modulated by the resonance between “spontaneous” and “stimulus-driven” oscillations. This gamma resonance can be precisely controlled by the synaptic plasticity of thalamocortical connections, and cortical response is regulated differentially according to the resonance condition. The mechanism produces a selective synchronization between the afferent and downstream neural population. Our simulation results explain experimental observations such as stimulus-dependent synchronization between the thalamus and the cortex at different oscillation frequencies. The model generally shows how sensory information can be selectively routed depending on its frequency components. In the nervous system, a network of neurons shows interesting population activities. One example is a various frequency of synchronized oscillations which are thought to be important to sensory functions. In particular, it has been reported that gamma frequency rhythms (30∼70Hz) in the cortex can significantly regulate the responses to visual stimuli. In this study, we further investigate the mechanism by which the nervous system can control the effect of gamma oscillation on the modulation of neural responses. We found that the sensory response of the visual cortex strongly depends on the extent of synchronization between external stimulus rhythms and spontaneous gamma oscillations in the cortical network. Furthermore, the simulation results show that the plasticity of the neural circuit can modulate the frequency of spontaneous gamma oscillations, thus readily controlling neural population responsiveness. This finding is related to the question of how the brain efficiently interprets external input signals under various conditions, using its internal neural connectivity. Our study provides insight into this question.
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23
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Kumar A, Bodhinathan K, Foster TC. Susceptibility to Calcium Dysregulation during Brain Aging. Front Aging Neurosci 2009; 1:2. [PMID: 20552053 PMCID: PMC2874411 DOI: 10.3389/neuro.24.002.2009] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/27/2009] [Indexed: 01/06/2023] Open
Abstract
Calcium (Ca(2+)) is a highly versatile intracellular signaling molecule that is essential for regulating a variety of cellular and physiological processes ranging from fertilization to programmed cell death. Research has provided ample evidence that brain aging is associated with altered Ca(2+) homeostasis. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during senescence. The current review takes a broader perspective, assessing age-related changes in Ca(2+) sources, Ca(2+) sequestration, and Ca(2+) binding proteins throughout the nervous system. The nature of altered Ca(2+) homeostasis is cell specific and may represent a deficit or a compensatory mechanism, producing complex patterns of impaired cellular function. Incorporating the knowledge of the complexity of age-related alterations in Ca(2+) homeostasis will positively shape the development of highly effective therapeutics to treat brain disorders.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida Gainesville, FL, USA
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24
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Ryan BK, Vollmayr B, Klyubin I, Gass P, Rowan MJ. Persistent inhibition of hippocampal long-term potentiation in vivo by learned helplessness stress. Hippocampus 2009; 20:758-67. [DOI: 10.1002/hipo.20677] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Aton SJ, Seibt J, Dumoulin MC, Coleman T, Shiraishi M, Frank MG. The sedating antidepressant trazodone impairs sleep-dependent cortical plasticity. PLoS One 2009; 4:e6078. [PMID: 19568418 PMCID: PMC2699540 DOI: 10.1371/journal.pone.0006078] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 06/02/2009] [Indexed: 01/06/2023] Open
Abstract
Background Recent findings indicate that certain classes of hypnotics that target GABAA receptors impair sleep-dependent brain plasticity. However, the effects of hypnotics acting at monoamine receptors (e.g., the antidepressant trazodone) on this process are unknown. We therefore assessed the effects of commonly-prescribed medications for the treatment of insomnia (trazodone and the non-benzodiazepine GABAA receptor agonists zaleplon and eszopiclone) in a canonical model of sleep-dependent, in vivo synaptic plasticity in the primary visual cortex (V1) known as ocular dominance plasticity. Methodology/Principal Findings After a 6-h baseline period of sleep/wake polysomnographic recording, cats underwent 6 h of continuous waking combined with monocular deprivation (MD) to trigger synaptic remodeling. Cats subsequently received an i.p. injection of either vehicle, trazodone (10 mg/kg), zaleplon (10 mg/kg), or eszopiclone (1–10 mg/kg), and were allowed an 8-h period of post-MD sleep before ocular dominance plasticity was assessed. We found that while zaleplon and eszopiclone had profound effects on sleeping cortical electroencephalographic (EEG) activity, only trazodone (which did not alter EEG activity) significantly impaired sleep-dependent consolidation of ocular dominance plasticity. This was associated with deficits in both the normal depression of V1 neuronal responses to deprived-eye stimulation, and potentiation of responses to non-deprived eye stimulation, which accompany ocular dominance plasticity. Conclusions/Significance Taken together, our data suggest that the monoamine receptors targeted by trazodone play an important role in sleep-dependent consolidation of synaptic plasticity. They also demonstrate that changes in sleep architecture are not necessarily reliable predictors of how hypnotics affect sleep-dependent neural functions.
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Affiliation(s)
- Sara J. Aton
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Julie Seibt
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Michelle C. Dumoulin
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tammi Coleman
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Mia Shiraishi
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Marcos G. Frank
- Department of Neuroscience, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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26
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Inaba M, Maruyama T, Yoshimura Y, Hosoi H, Komatsu Y. Facilitation of low-frequency stimulation-induced long-term potentiation by endogenous noradrenaline and serotonin in developing rat visual cortex. Neurosci Res 2009; 64:191-8. [DOI: 10.1016/j.neures.2009.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 02/25/2009] [Accepted: 02/26/2009] [Indexed: 10/21/2022]
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27
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The ratio of NR2A/B NMDA receptor subunits determines the qualities of ocular dominance plasticity in visual cortex. Proc Natl Acad Sci U S A 2009; 106:5377-82. [PMID: 19276107 DOI: 10.1073/pnas.0808104106] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bidirectional synaptic plasticity during development ensures that appropriate synapses in the brain are strengthened and maintained while inappropriate connections are weakened and eliminated. This plasticity is well illustrated in mouse visual cortex, where monocular deprivation during early postnatal development leads to a rapid depression of inputs from the deprived eye and a delayed strengthening of inputs from the non-deprived eye. The mechanisms that control these bidirectional synaptic modifications remain controversial. Here we demonstrate, both in vitro and in vivo, that genetic deletion or reduction of the NR2A NMDA receptor subunit impairs activity-dependent weakening of synapses and enhances the strengthening of synapses. Although brief monocular deprivation in juvenile WT mice normally causes a profound depression of the deprived-eye response without a change in the non-deprived eye response, NR2A-knockout mice fail to exhibit deprivation-induced depression and instead exhibit precocious potentiation of the non-deprived eye inputs. These data support the hypothesis that a reduction in the NR2A/B ratio during monocular deprivation is permissive for the compensatory potentiation of non-deprived inputs.
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