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Li Y. Differential behaviors of calcium-induced calcium release in one dimensional dendrite by Nernst-Planck equation, cable model and pure diffusion model. Cogn Neurodyn 2024; 18:1285-1305. [PMID: 38826668 PMCID: PMC11143177 DOI: 10.1007/s11571-023-09952-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 02/16/2023] [Accepted: 03/08/2023] [Indexed: 06/04/2024] Open
Abstract
The source and dynamics of calcium is the key factor that regulates dendritic integration. Apart from the voltage-gated and ligand-gated calcium influx, an important source of calcium is from inner store of endoplasmic reticulum with a regenerative process of calcium-induced calcium release (CICR). To trigger this process, inositol 1,4,5-trisphosphate (IP3) and calcium are needed to satisfy certain requirements. The aim of our paper is to investigate how the CICR depends on the dynamics of membrane potential. We utilize one dimensional dendritic model to calculate membrane potential by Nernst-Planck Equation (NPE) and cable model and Pure Diffusion (PD) model, computational simulations are carried out to inject the calcium influx by synaptic stimulation and to predict subsequent CICR and calcium wave propagation. Our results demonstrate that CICR initiation and calcium wave propagation have much difference between electro-diffusion process of NPE and cable model. We find that cable model has lower threshold of IP3 stimulation to trigger CICR but is more difficult for calcium propagation than NPE, PD model requires even higher threshold of IP3 to initiate CICR process and calcium duration is shorter than NPE; the regenerative calcium wave propagates with faster speed in NPE than that in cable model and in PD model. Our work addresses the important role of electro-diffusion dynamics of charged ions in regulating CICR process in dendritic structure; and provides theoretical predictions for neurological process which requires sustaining calcium for downstream signaling processes.
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Affiliation(s)
- Yinyun Li
- School of Systems Science, Beijing Normal University, Beijing, 100875 China
- Department of Mathematics and Statistics, Washington State University Vancouver, Vancouver, USA
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Intracellular calcium release: A conductor of compartmentalized dendritic plasticity. Cell 2022; 185:1627-1629. [DOI: 10.1016/j.cell.2022.04.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 11/22/2022]
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O’Hare JK, Gonzalez KC, Herrlinger SA, Hirabayashi Y, Hewitt VL, Blockus H, Szoboszlay M, Rolotti SV, Geiller TC, Negrean A, Chelur V, Polleux F, Losonczy A. Compartment-specific tuning of dendritic feature selectivity by intracellular Ca 2+ release. Science 2022; 375:eabm1670. [PMID: 35298275 PMCID: PMC9667905 DOI: 10.1126/science.abm1670] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dendritic calcium signaling is central to neural plasticity mechanisms that allow animals to adapt to the environment. Intracellular calcium release (ICR) from the endoplasmic reticulum has long been thought to shape these mechanisms. However, ICR has not been investigated in mammalian neurons in vivo. We combined electroporation of single CA1 pyramidal neurons, simultaneous imaging of dendritic and somatic activity during spatial navigation, optogenetic place field induction, and acute genetic augmentation of ICR cytosolic impact to reveal that ICR supports the establishment of dendritic feature selectivity and shapes integrative properties determining output-level receptive fields. This role for ICR was more prominent in apical than in basal dendrites. Thus, ICR cooperates with circuit-level architecture in vivo to promote the emergence of behaviorally relevant plasticity in a compartment-specific manner.
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Affiliation(s)
- Justin K. O’Hare
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Kevin C. Gonzalez
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Stephanie A. Herrlinger
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Yusuke Hirabayashi
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo; Tokyo, Japan
| | - Victoria L. Hewitt
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Heike Blockus
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Miklos Szoboszlay
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Sebi V. Rolotti
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Tristan C. Geiller
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Adrian Negrean
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
| | - Vikas Chelur
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
| | - Franck Polleux
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
- Kavli Institute for Brain Science, Columbia University; New York, NY, 10027, United States
| | - Attila Losonczy
- Department of Neuroscience, Columbia University; New York, NY, 10027, United States
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, United States
- Kavli Institute for Brain Science, Columbia University; New York, NY, 10027, United States
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Abdelfattah AS, Ahuja S, Akkin T, Allu SR, Brake J, Boas DA, Buckley EM, Campbell RE, Chen AI, Cheng X, Čižmár T, Costantini I, De Vittorio M, Devor A, Doran PR, El Khatib M, Emiliani V, Fomin-Thunemann N, Fainman Y, Fernandez-Alfonso T, Ferri CGL, Gilad A, Han X, Harris A, Hillman EMC, Hochgeschwender U, Holt MG, Ji N, Kılıç K, Lake EMR, Li L, Li T, Mächler P, Miller EW, Mesquita RC, Nadella KMNS, Nägerl UV, Nasu Y, Nimmerjahn A, Ondráčková P, Pavone FS, Perez Campos C, Peterka DS, Pisano F, Pisanello F, Puppo F, Sabatini BL, Sadegh S, Sakadzic S, Shoham S, Shroff SN, Silver RA, Sims RR, Smith SL, Srinivasan VJ, Thunemann M, Tian L, Tian L, Troxler T, Valera A, Vaziri A, Vinogradov SA, Vitale F, Wang LV, Uhlířová H, Xu C, Yang C, Yang MH, Yellen G, Yizhar O, Zhao Y. Neurophotonic tools for microscopic measurements and manipulation: status report. NEUROPHOTONICS 2022; 9:013001. [PMID: 35493335 PMCID: PMC9047450 DOI: 10.1117/1.nph.9.s1.013001] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Neurophotonics was launched in 2014 coinciding with the launch of the BRAIN Initiative focused on development of technologies for advancement of neuroscience. For the last seven years, Neurophotonics' agenda has been well aligned with this focus on neurotechnologies featuring new optical methods and tools applicable to brain studies. While the BRAIN Initiative 2.0 is pivoting towards applications of these novel tools in the quest to understand the brain, this status report reviews an extensive and diverse toolkit of novel methods to explore brain function that have emerged from the BRAIN Initiative and related large-scale efforts for measurement and manipulation of brain structure and function. Here, we focus on neurophotonic tools mostly applicable to animal studies. A companion report, scheduled to appear later this year, will cover diffuse optical imaging methods applicable to noninvasive human studies. For each domain, we outline the current state-of-the-art of the respective technologies, identify the areas where innovation is needed, and provide an outlook for the future directions.
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Affiliation(s)
- Ahmed S. Abdelfattah
- Brown University, Department of Neuroscience, Providence, Rhode Island, United States
| | - Sapna Ahuja
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Taner Akkin
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Srinivasa Rao Allu
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Joshua Brake
- Harvey Mudd College, Department of Engineering, Claremont, California, United States
| | - David A. Boas
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Erin M. Buckley
- Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Emory University, Department of Pediatrics, Atlanta, Georgia, United States
| | - Robert E. Campbell
- University of Tokyo, Department of Chemistry, Tokyo, Japan
- University of Alberta, Department of Chemistry, Edmonton, Alberta, Canada
| | - Anderson I. Chen
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Xiaojun Cheng
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Tomáš Čižmár
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Irene Costantini
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Biology, Florence, Italy
- National Institute of Optics, National Research Council, Rome, Italy
| | - Massimo De Vittorio
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Anna Devor
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Patrick R. Doran
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Mirna El Khatib
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | | | - Natalie Fomin-Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Yeshaiahu Fainman
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Tomas Fernandez-Alfonso
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Christopher G. L. Ferri
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Ariel Gilad
- The Hebrew University of Jerusalem, Institute for Medical Research Israel–Canada, Department of Medical Neurobiology, Faculty of Medicine, Jerusalem, Israel
| | - Xue Han
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Andrew Harris
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | | | - Ute Hochgeschwender
- Central Michigan University, Department of Neuroscience, Mount Pleasant, Michigan, United States
| | - Matthew G. Holt
- University of Porto, Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
| | - Na Ji
- University of California Berkeley, Department of Physics, Berkeley, California, United States
| | - Kıvılcım Kılıç
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evelyn M. R. Lake
- Yale School of Medicine, Department of Radiology and Biomedical Imaging, New Haven, Connecticut, United States
| | - Lei Li
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Tianqi Li
- University of Minnesota, Department of Biomedical Engineering, Minneapolis, Minnesota, United States
| | - Philipp Mächler
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Evan W. Miller
- University of California Berkeley, Departments of Chemistry and Molecular & Cell Biology and Helen Wills Neuroscience Institute, Berkeley, California, United States
| | | | | | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience University of Bordeaux & CNRS, Bordeaux, France
| | - Yusuke Nasu
- University of Tokyo, Department of Chemistry, Tokyo, Japan
| | - Axel Nimmerjahn
- Salk Institute for Biological Studies, Waitt Advanced Biophotonics Center, La Jolla, California, United States
| | - Petra Ondráčková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Francesco S. Pavone
- National Institute of Optics, National Research Council, Rome, Italy
- University of Florence, European Laboratory for Non-Linear Spectroscopy, Department of Physics, Florence, Italy
| | - Citlali Perez Campos
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Darcy S. Peterka
- Columbia University, Zuckerman Mind Brain Behavior Institute, New York, United States
| | - Filippo Pisano
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Ferruccio Pisanello
- Istituto Italiano di Tecnologia, Center for Biomolecular Nanotechnologies, Arnesano, Italy
| | - Francesca Puppo
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Bernardo L. Sabatini
- Harvard Medical School, Howard Hughes Medical Institute, Department of Neurobiology, Boston, Massachusetts, United States
| | - Sanaz Sadegh
- University of California San Diego, Departments of Neurosciences, La Jolla, California, United States
| | - Sava Sakadzic
- Massachusetts General Hospital, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Shy Shoham
- New York University Grossman School of Medicine, Tech4Health and Neuroscience Institutes, New York, New York, United States
| | - Sanaya N. Shroff
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - R. Angus Silver
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Ruth R. Sims
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Spencer L. Smith
- University of California Santa Barbara, Department of Electrical and Computer Engineering, Santa Barbara, California, United States
| | - Vivek J. Srinivasan
- New York University Langone Health, Departments of Ophthalmology and Radiology, New York, New York, United States
| | - Martin Thunemann
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Lei Tian
- Boston University, Departments of Electrical Engineering and Biomedical Engineering, Boston, Massachusetts, United States
| | - Lin Tian
- University of California Davis, Department of Biochemistry and Molecular Medicine, Davis, California, United States
| | - Thomas Troxler
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Antoine Valera
- University College London, Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Alipasha Vaziri
- Rockefeller University, Laboratory of Neurotechnology and Biophysics, New York, New York, United States
- The Rockefeller University, The Kavli Neural Systems Institute, New York, New York, United States
| | - Sergei A. Vinogradov
- University of Pennsylvania, Perelman School of Medicine, Department of Biochemistry and Biophysics, Philadelphia, Pennsylvania, United States
- University of Pennsylvania, School of Arts and Sciences, Department of Chemistry, Philadelphia, Pennsylvania, United States
| | - Flavia Vitale
- Center for Neuroengineering and Therapeutics, Departments of Neurology, Bioengineering, Physical Medicine and Rehabilitation, Philadelphia, Pennsylvania, United States
| | - Lihong V. Wang
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
| | - Hana Uhlířová
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Chris Xu
- Cornell University, School of Applied and Engineering Physics, Ithaca, New York, United States
| | - Changhuei Yang
- California Institute of Technology, Departments of Electrical Engineering, Bioengineering and Medical Engineering, Pasadena, California, United States
| | - Mu-Han Yang
- University of California San Diego, Department of Electrical and Computer Engineering, La Jolla, California, United States
| | - Gary Yellen
- Harvard Medical School, Department of Neurobiology, Boston, Massachusetts, United States
| | - Ofer Yizhar
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
| | - Yongxin Zhao
- Carnegie Mellon University, Department of Biological Sciences, Pittsburgh, Pennsylvania, United States
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The Impact of SST and PV Interneurons on Nonlinear Synaptic Integration in the Neocortex. eNeuro 2021; 8:ENEURO.0235-21.2021. [PMID: 34400470 PMCID: PMC8425965 DOI: 10.1523/eneuro.0235-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/26/2021] [Accepted: 08/09/2021] [Indexed: 01/19/2023] Open
Abstract
Excitatory synaptic inputs arriving at the dendrites of a neuron can engage active mechanisms that nonlinearly amplify the depolarizing currents. This supralinear synaptic integration is subject to modulation by inhibition. However, the specific rules by which different subtypes of interneurons affect the modulation have remained largely elusive. To examine how inhibition influences active synaptic integration, we optogenetically manipulated the activity of the following two subtypes of interneurons: dendrite-targeting somatostatin-expressing (SST) interneurons; and perisomatic-targeting parvalbumin-expressing (PV) interneurons. In acute slices of mouse primary visual cortex, electrical stimulation evoked nonlinear synaptic integration that depended on NMDA receptors. Optogenetic activation of SST interneurons in conjunction with electrical stimulation resulted in predominantly divisive inhibitory gain control, reducing the magnitude of the supralinear response without affecting its threshold. PV interneuron activation, on the other hand, had a minimal effect on the supralinear response. Together, these results delineate the roles for SST and PV neurons in active synaptic integration. Differential effects of inhibition by SST and PV interneurons likely increase the computational capacity of the pyramidal neurons in modulating the nonlinear integration of synaptic output.
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Neymotin SA, Dura-Bernal S, Lakatos P, Sanger TD, Lytton WW. Multitarget Multiscale Simulation for Pharmacological Treatment of Dystonia in Motor Cortex. Front Pharmacol 2016; 7:157. [PMID: 27378922 PMCID: PMC4906029 DOI: 10.3389/fphar.2016.00157] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/30/2016] [Indexed: 12/20/2022] Open
Abstract
A large number of physiomic pathologies can produce hyperexcitability in cortex. Depending on severity, cortical hyperexcitability may manifest clinically as a hyperkinetic movement disorder or as epilpesy. We focus here on dystonia, a movement disorder that produces involuntary muscle contractions and involves pathology in multiple brain areas including basal ganglia, thalamus, cerebellum, and sensory and motor cortices. Most research in dystonia has focused on basal ganglia, while much pharmacological treatment is provided directly at muscles to prevent contraction. Motor cortex is another potential target for therapy that exhibits pathological dynamics in dystonia, including heightened activity and altered beta oscillations. We developed a multiscale model of primary motor cortex, ranging from molecular, up to cellular, and network levels, containing 1715 compartmental model neurons with multiple ion channels and intracellular molecular dynamics. We wired the model based on electrophysiological data obtained from mouse motor cortex circuit mapping experiments. We used the model to reproduce patterns of heightened activity seen in dystonia by applying independent random variations in parameters to identify pathological parameter sets. These models demonstrated degeneracy, meaning that there were many ways of obtaining the pathological syndrome. There was no single parameter alteration which would consistently distinguish pathological from physiological dynamics. At higher dimensions in parameter space, we were able to use support vector machines to distinguish the two patterns in different regions of space and thereby trace multitarget routes from dystonic to physiological dynamics. These results suggest the use of in silico models for discovery of multitarget drug cocktails.
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Affiliation(s)
- Samuel A Neymotin
- Department Physiology and Pharmacology, SUNY Downstate Medical Center, State University of New YorkBrooklyn, NY, USA; Department Neuroscience, Yale University School of MedicineNew Haven, CT, USA
| | - Salvador Dura-Bernal
- Department Physiology and Pharmacology, SUNY Downstate Medical Center, State University of New York Brooklyn, NY, USA
| | - Peter Lakatos
- Nathan S. Kline Institute for Psychiatric Research Orangeburg, NY, USA
| | - Terence D Sanger
- Department Biomedical Engineering, University of Southern CaliforniaLos Angeles, CA, USA; Division Neurology, Child Neurology and Movement Disorders, Children's Hospital Los AngelesLos Angeles, CA, USA
| | - William W Lytton
- Department Physiology and Pharmacology, SUNY Downstate Medical Center, State University of New YorkBrooklyn, NY, USA; Department Neurology, SUNY Downstate Medical CenterBrooklyn, NY, USA; Department Neurology, Kings County Hospital CenterBrooklyn, NY, USA; The Robert F. Furchgott Center for Neural and Behavioral ScienceBrooklyn, NY, US
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Neymotin SA, McDougal RA, Bulanova AS, Zeki M, Lakatos P, Terman D, Hines ML, Lytton WW. Calcium regulation of HCN channels supports persistent activity in a multiscale model of neocortex. Neuroscience 2016; 316:344-66. [PMID: 26746357 PMCID: PMC4724569 DOI: 10.1016/j.neuroscience.2015.12.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/16/2015] [Accepted: 12/21/2015] [Indexed: 01/08/2023]
Abstract
Neuronal persistent activity has been primarily assessed in terms of electrical mechanisms, without attention to the complex array of molecular events that also control cell excitability. We developed a multiscale neocortical model proceeding from the molecular to the network level to assess the contributions of calcium (Ca(2+)) regulation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in providing additional and complementary support of continuing activation in the network. The network contained 776 compartmental neurons arranged in the cortical layers, connected using synapses containing AMPA/NMDA/GABAA/GABAB receptors. Metabotropic glutamate receptors (mGluR) produced inositol triphosphate (IP3) which caused the release of Ca(2+) from endoplasmic reticulum (ER) stores, with reuptake by sarco/ER Ca(2+)-ATP-ase pumps (SERCA), and influence on HCN channels. Stimulus-induced depolarization led to Ca(2+) influx via NMDA and voltage-gated Ca(2+) channels (VGCCs). After a delay, mGluR activation led to ER Ca(2+) release via IP3 receptors. These factors increased HCN channel conductance and produced firing lasting for ∼1min. The model displayed inter-scale synergies among synaptic weights, excitation/inhibition balance, firing rates, membrane depolarization, Ca(2+) levels, regulation of HCN channels, and induction of persistent activity. The interaction between inhibition and Ca(2+) at the HCN channel nexus determined a limited range of inhibition strengths for which intracellular Ca(2+) could prepare population-specific persistent activity. Interactions between metabotropic and ionotropic inputs to the neuron demonstrated how multiple pathways could contribute in a complementary manner to persistent activity. Such redundancy and complementarity via multiple pathways is a critical feature of biological systems. Mediation of activation at different time scales, and through different pathways, would be expected to protect against disruption, in this case providing stability for persistent activity.
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Affiliation(s)
- S A Neymotin
- Department of Physiology & Pharmacology, SUNY Downstate, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
| | - R A McDougal
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
| | - A S Bulanova
- Department of Physiology & Pharmacology, SUNY Downstate, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
| | - M Zeki
- Department of Mathematics, Zirve University, 27260 Gaziantep, Turkey.
| | - P Lakatos
- Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
| | - D Terman
- Department of Mathematics, The Ohio State University, 231 W 18th Avenue, Columbus, OH 43210, USA.
| | - M L Hines
- Department of Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
| | - W W Lytton
- Department of Physiology & Pharmacology, SUNY Downstate, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; Department of Neurology, SUNY Downstate, 450 Clarkson Avenue, Brooklyn, NY 11203, USA; Department Neurology, Kings County Hospital Center, 451 Clarkson Avenue, Brooklyn, NY 11203, USA.
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Neymotin SA, McDougal RA, Sherif MA, Fall CP, Hines ML, Lytton WW. Neuronal calcium wave propagation varies with changes in endoplasmic reticulum parameters: a computer model. Neural Comput 2015; 27:898-924. [PMID: 25734493 PMCID: PMC4386758 DOI: 10.1162/neco_a_00712] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Calcium (Ca²⁺) waves provide a complement to neuronal electrical signaling, forming a key part of a neuron's second messenger system. We developed a reaction-diffusion model of an apical dendrite with diffusible inositol triphosphate (IP₃), diffusible Ca²⁺, IP₃ receptors (IP₃Rs), endoplasmic reticulum (ER) Ca²⁺ leak, and ER pump (SERCA) on ER. Ca²⁺ is released from ER stores via IP₃Rs upon binding of IP₃ and Ca²⁺. This results in Ca²⁺-induced-Ca²⁺-release (CICR) and increases Ca²⁺ spread. At least two modes of Ca²⁺ wave spread have been suggested: a continuous mode based on presumed relative homogeneity of ER within the cell and a pseudo-saltatory model where Ca²⁺ regeneration occurs at discrete points with diffusion between them. We compared the effects of three patterns of hypothesized IP₃R distribution: (1) continuous homogeneous ER, (2) hotspots with increased IP₃R density (IP₃R hotspots), and (3) areas of increased ER density (ER stacks). All three modes produced Ca²⁺ waves with velocities similar to those measured in vitro (approximately 50-90 μm /sec). Continuous ER showed high sensitivity to IP₃R density increases, with time to onset reduced and speed increased. Increases in SERCA density resulted in opposite effects. The measures were sensitive to changes in density and spacing of IP₃R hotspots and stacks. Increasing the apparent diffusion coefficient of Ca²⁺ substantially increased wave speed. An extended electrochemical model, including voltage-gated calcium channels and AMPA synapses, demonstrated that membrane priming via AMPA stimulation enhances subsequent Ca²⁺ wave amplitude and duration. Our modeling suggests that pharmacological targeting of IP₃Rs and SERCA could allow modulation of Ca²⁺ wave propagation in diseases where Ca²⁺ dysregulation has been implicated.
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Affiliation(s)
- Samuel A Neymotin
- Department of Physiology and Pharmacology, SUNY Downstate, Brooklyn, NY, 11203, and Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, U.S.A.
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Sugawara Y, Echigo R, Kashima K, Minami H, Watanabe M, Nishikawa Y, Muranishi M, Yoneda M, Ohno-Shosaku T. Intracellular calcium level is an important factor influencing ion channel modulations by PLC-coupled metabotropic receptors in hippocampal neurons. Brain Res 2013; 1512:9-21. [PMID: 23548601 DOI: 10.1016/j.brainres.2013.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 10/27/2022]
Abstract
Signaling pathways involving phospholipase C (PLC) are involved in various neural functions. Understanding how these pathways are regulated will lead to a better understanding of their roles in neural functions. Previous studies demonstrated that receptor-driven PLCβ activation depends on intracellular Ca(2+) concentration ([Ca(2+)]i), suggesting the possibility that PLCβ-dependent cellular responses are basically Ca(2+) dependent. To test this possibility, we examined whether modulations of ion channels driven by PLC-coupled metabotropic receptors are sensitive to [Ca(2+)]i using cultured hippocampal neurons. Muscarinic activation triggered an inward current at -100 mV (the equilibrium potential for K(+)) in a subpopulation of neurons. This current response was suppressed by pirenzepine (an M1-preferring antagonist), PLC inhibitor, non-selective cation channel blocker, and lowering [Ca(2+)]i. Using the neurons showing no response at -100 mV, effects of muscarinic activation on K(+) channels were examined at -40 mV. Muscarinic activation induced a transient decrease of the holding outward current. This current response was mimicked and occluded by XE991, an M-current K(+) channel blocker, suppressed by pirenzepine, PLC inhibitor and lowering [Ca(2+)]i, and enhanced by elevating [Ca(2+)]i. Similar results were obtained when group I metabotropic glutamate receptors were activated instead of muscarinic receptors. These results clearly show that ion channel modulations driven by PLC-coupled metabotropic receptors are dependent on [Ca(2+)]i, supporting the hypothesis that cellular responses induced by receptor-driven PLCβ activation are basically Ca(2+) dependent.
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Affiliation(s)
- Yuto Sugawara
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
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10
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Sekerková G, Watanabe M, Martina M, Mugnaini E. Differential distribution of phospholipase C beta isoforms and diaglycerol kinase-beta in rodents cerebella corroborates the division of unipolar brush cells into two major subtypes. Brain Struct Funct 2013; 219:719-49. [PMID: 23503970 DOI: 10.1007/s00429-013-0531-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 02/19/2013] [Indexed: 11/26/2022]
Abstract
Sublineage diversification of specific neural cell classes occurs in complex as well as simply organized regions of the central and peripheral nervous systems; the significance of the phenomenon, however, remains insufficiently understood. The unipolar brush cells (UBCs) are glutamatergic cerebellar interneurons that occur at high density in vestibulocerebellum. As they are classified into subsets that differ in chemical phenotypes, intrinsic properties, and lobular distribution, they represent a valuable neuronal model to study subclass diversification. In this study, we show that cerebellar UBCs of adult rats and mice form two subclasses-type I and type II UBCs-defined by somatodendritic expression of calretinin (CR), mGluR1α, phospholipases PLCβ1 and PLCβ4, and diacylglycerol kinase-beta (DGKβ). We demonstrate that PLCβ1 is associated only with the CR(+) type I UBCs, while PLCβ4 and DGKβ are exclusively present in mGluR1α(+) type II UBCs. Notably, all PLCβ4(+) UBCs, representing about 2/3 of entire UBC population, also express mGluR1α. Furthermore, our data show that the sum of CR(+) type I UBCs and mGluR1α(+) type II UBCs accounts for the entire UBC class identified with Tbr2 immunolabeling. The two UBC subtypes also show a very different albeit somehow overlapping topographical distribution as illustrated by detailed cerebellar maps in this study. Our data not only complement and extend the previous knowledge on the diversity and subclass specificity of the chemical phenotypes within the UBC population, but also provide a new angle to the understanding of the signaling networks in type I and type II UBCs.
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Affiliation(s)
- Gabriella Sekerková
- Department of Cellular and Molecular Biology, Feinberg School of Medicine, Northwestern University, 5-465 Searle bldg. 320 E. Superior str, Chicago, IL, 60611, USA,
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11
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Early presynaptic and postsynaptic calcium signaling abnormalities mask underlying synaptic depression in presymptomatic Alzheimer's disease mice. J Neurosci 2012; 32:8341-53. [PMID: 22699914 DOI: 10.1523/jneurosci.0936-12.2012] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD)-linked presenilin (PS) mutations result in pronounced endoplasmic reticulum calcium disruptions that occur before detectable histopathology and cognitive deficits. More subtly, these early AD-linked calcium alterations also reset neurophysiological homeostasis, such that calcium-dependent presynaptic and postsynaptic signaling appear functionally normal yet are actually operating under aberrant calcium signaling systems. In these 3xTg-AD mouse brains, upregulated ryanodine receptor (RyR) activity is associated with a shift toward synaptic depression, likely through a reduction in presynaptic vesicle stores and increased postsynaptic outward currents through small-conductance calcium-activated potassium SK2 channels. The deviant RyR-calcium involvement in the 3xTg-AD mice also compensates for an intrinsic predisposition for hippocampal long-term depression (LTD) and reduced long-term potentiation (LTP). In this study, we detail the impact of disrupted RyR-mediated calcium stores on synaptic transmission properties, LTD, and calcium-activated membrane channels of hippocampal CA1 pyramidal neurons in presymptomatic 3xTg-AD mice. Using electrophysiological recordings in young 3xTg-AD and nontransgenic (NonTg) hippocampal slices, we show that increased RyR-evoked calcium release in 3xTg-AD mice "normalizes" an altered synaptic transmission system operating under a shifted homeostatic state that is not present in NonTg mice. In the process, we uncover compensatory signaling mechanisms recruited early in the disease process that counterbalance the disrupted RyR-calcium dynamics, namely increases in presynaptic spontaneous vesicle release, altered probability of vesicle release, and upregulated postsynaptic SK channel activity. Because AD is increasingly recognized as a "synaptic disease," calcium-mediated signaling alterations may serve as a proximal trigger for the synaptic degradation driving the cognitive loss in AD.
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12
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Devor A, Sakadžić S, Srinivasan VJ, Yaseen MA, Nizar K, Saisan PA, Tian P, Dale AM, Vinogradov SA, Franceschini MA, Boas DA. Frontiers in optical imaging of cerebral blood flow and metabolism. J Cereb Blood Flow Metab 2012; 32:1259-76. [PMID: 22252238 PMCID: PMC3390808 DOI: 10.1038/jcbfm.2011.195] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In vivo optical imaging of cerebral blood flow (CBF) and metabolism did not exist 50 years ago. While point optical fluorescence and absorption measurements of cellular metabolism and hemoglobin concentrations had already been introduced by then, point blood flow measurements appeared only 40 years ago. The advent of digital cameras has significantly advanced two-dimensional optical imaging of neuronal, metabolic, vascular, and hemodynamic signals. More recently, advanced laser sources have enabled a variety of novel three-dimensional high-spatial-resolution imaging approaches. Combined, as we discuss here, these methods are permitting a multifaceted investigation of the local regulation of CBF and metabolism with unprecedented spatial and temporal resolution. Through multimodal combination of these optical techniques with genetic methods of encoding optical reporter and actuator proteins, the future is bright for solving the mysteries of neurometabolic and neurovascular coupling and translating them to clinical utility.
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Affiliation(s)
- Anna Devor
- Department of Neurosciences, UCSD, La Jolla, CA, USA.
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13
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Cholinergic induction of input-specific late-phase LTP via localized Ca2+ release in the visual cortex. J Neurosci 2012; 32:4520-30. [PMID: 22457499 DOI: 10.1523/jneurosci.4577-11.2012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Acetylcholine facilitates long-term potentiation (LTP) and long-term depression (LTD), substrates of learning, memory, and sensory processing, in which acetylcholine also plays a crucial role. Ca(2+) ions serve as a canonical regulator of LTP/LTD but little is known about the effect of acetylcholine on intracellular Ca(2+) dynamics. Here, we investigated dendritic Ca(2+) dynamics evoked by synaptic stimulation and the resulting LTP/LTD in layer 2/3 pyramidal neurons of the rat visual cortex. Under muscarinic stimulation, single-shock electrical stimulation (SES) inducing ∼20 mV EPSP, applied via a glass electrode located ∼10 μm from the basal dendrite, evoked NMDA receptor-dependent fast Ca(2+) transients and the subsequent Ca(2+) release from the inositol 1,4,5-trisphosphate (IP(3))-sensitive stores. These secondary dendritic Ca(2+) transients were highly localized within 10 μm from the center (SD = 5.0 μm). The dendritic release of Ca(2+) was a prerequisite for input-specific muscarinic LTP (LTPm). Without the secondary Ca(2+) release, only muscarinic LTD (LTDm) was induced. D(-)-2-amino-5-phosphopentanoic acid and intracellular heparin blocked LTPm as well as dendritic Ca(2+) release. A single burst consisting of 3 EPSPs with weak stimulus intensities instead of the SES also induced secondary Ca(2+) release and LTPm. LTPm and LTDm were protein synthesis-dependent. Furthermore, LTPm was confined to specific dendritic compartments and not inducible in distal apical dendrites. Thus, cholinergic activation facilitated selectively compartment-specific induction of late-phase LTP through IP(3)-dependent Ca(2+) release.
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14
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Siegel F, Lohmann C. Probing synaptic function in dendrites with calcium imaging. Exp Neurol 2012; 242:27-32. [PMID: 22374356 DOI: 10.1016/j.expneurol.2012.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 11/22/2011] [Accepted: 02/13/2012] [Indexed: 11/19/2022]
Abstract
Calcium imaging has become a widely used technique to probe neuronal activity on the cellular and subcellular levels. In contrast to standard electrophysiological methods, calcium imaging resolves sub- and suprathreshold activation patterns in structures as small as fine dendritic branches and spines. This review highlights recent findings gained on the subcellular level using calcium imaging, with special emphasis on synaptic transmission and plasticity in individual spines. Since imaging allows monitoring activity across populations of synapses, it has recently been adopted to investigate how dendrites integrate information from many synapses. Future experiments, ideally carried out in vivo, will reveal how the dendritic tree integrates and computes afferent signals. For example, it is now possible to directly test the concept that dendritic inputs are clustered and that single dendrites or dendritic stretches act as independent computational units.
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15
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Karpova A, Bär J, Kreutz MR. Long-distance signaling from synapse to nucleus via protein messengers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 970:355-76. [PMID: 22351064 DOI: 10.1007/978-3-7091-0932-8_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The communication between synapses and the cell nucleus has attracted considerable interest for many years. This interest is largely fueled by the idea that synapse-to-nucleus signaling might specifically induce the expression of genes that make long-term memory "stick." However, despite many years of research, it is still essentially unclear how synaptic signals are conveyed to the nucleus, and it remains to a large degree enigmatic how activity-induced gene expression feeds back to synaptic function. In this chapter, we will focus on the activity-dependent synapto-nuclear trafficking of protein messengers and discuss the underlying mechanisms of their retrograde transport and their supposed functional role in neuronal plasticity.
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Affiliation(s)
- Anna Karpova
- PG Neuroplasticity, Leibniz Institute for Neurobiology, Brenneckestr.6, 39118 Magdeburg, Germany
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16
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Early calcium dysregulation in Alzheimer's disease: setting the stage for synaptic dysfunction. SCIENCE CHINA-LIFE SCIENCES 2011; 54:752-62. [PMID: 21786198 DOI: 10.1007/s11427-011-4205-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Accepted: 05/30/2011] [Indexed: 02/05/2023]
Abstract
Alzheimer's disease (AD) is an irreversible and progressive neurodegenerative disorder with no known cure or clear understanding of the mechanisms involved in the disease process. Amyloid plaques, neurofibrillary tangles and neuronal loss, though characteristic of AD, are late stage markers whose impact on the most devastating aspect of AD, namely memory loss and cognitive deficits, are still unclear. Recent studies demonstrate that structural and functional breakdown of synapses may be the underlying factor in AD-linked cognitive decline. One common element that presents with several features of AD is disrupted neuronal calcium signaling. Increased intracellular calcium levels are functionally linked to presenilin mutations, ApoE4 expression, amyloid plaques, tau tangles and synaptic dysfunction. In this review, we discuss the role of AD-linked calcium signaling alterations in neurons and how this may be linked to synaptic dysfunctions at both early and late stages of the disease.
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17
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Stutzmann GE, Mattson MP. Endoplasmic reticulum Ca(2+) handling in excitable cells in health and disease. Pharmacol Rev 2011; 63:700-27. [PMID: 21737534 DOI: 10.1124/pr.110.003814] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is a morphologically and functionally diverse organelle capable of integrating multiple extracellular and internal signals and generating adaptive cellular responses. It plays fundamental roles in protein synthesis and folding and in cellular responses to metabolic and proteotoxic stress. In addition, the ER stores and releases Ca(2+) in sophisticated scenarios that regulate a range of processes in excitable cells throughout the body, including muscle contraction and relaxation, endocrine regulation of metabolism, learning and memory, and cell death. One or more Ca(2+) ATPases and two types of ER membrane Ca(2+) channels (inositol trisphosphate and ryanodine receptors) are the major proteins involved in ER Ca(2+) uptake and release, respectively. There are also direct and indirect interactions of ER Ca(2+) stores with plasma membrane and mitochondrial Ca(2+)-regulating systems. Pharmacological agents that selectively modify ER Ca(2+) release or uptake have enabled studies that revealed many different physiological roles for ER Ca(2+) signaling. Several inherited diseases are caused by mutations in ER Ca(2+)-regulating proteins, and perturbed ER Ca(2+) homeostasis is implicated in a range of acquired disorders. Preclinical investigations suggest a therapeutic potential for use of agents that target ER Ca(2+) handling systems of excitable cells in disorders ranging from cardiac arrhythmias and skeletal muscle myopathies to Alzheimer disease.
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Affiliation(s)
- Grace E Stutzmann
- Department of Neuroscience, Rosalind Franklin University/The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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18
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Antic SD, Zhou WL, Moore AR, Short SM, Ikonomu KD. The decade of the dendritic NMDA spike. J Neurosci Res 2011; 88:2991-3001. [PMID: 20544831 DOI: 10.1002/jnr.22444] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the field of cortical cellular physiology, much effort has been invested in understanding thick apical dendrites of pyramidal neurons and the regenerative sodium and calcium spikes that take place in the apical trunk. Here we focus on thin dendrites of pyramidal cells (basal, oblique, and tuft dendrites), and we discuss one relatively novel form of an electrical signal ("NMDA spike") that is specific for these branches. Basal, oblique, and apical tuft dendrites receive a high density of glutamatergic synaptic contacts. Synchronous activation of 10-50 neighboring glutamatergic synapses triggers a local dendritic regenerative potential, NMDA spike/plateau, which is characterized by significant local amplitude (40-50 mV) and an extraordinary duration (up to several hundred milliseconds). The NMDA plateau potential, when it is initiated in an apical tuft dendrite, is able to maintain a good portion of that tuft in a sustained depolarized state. However, if NMDA-dominated plateau potentials originate in proximal segments of basal dendrites, they regularly bring the neuronal cell body into a sustained depolarized state, which resembles a cortical Up state. At each dendritic initiation site (basal, oblique, and tuft) an NMDA spike creates favorable conditions for causal interactions of active synaptic inputs, including the spatial or temporal binding of information, as well as processes of short-term and long-term synaptic modifications (e.g., long-term potentiation or long-term depression). Because of their strong amplitudes and durations, local dendritic NMDA spikes make up the cellular substrate for multisite independent subunit computations that enrich the computational power and repertoire of cortical pyramidal cells. We propose that NMDA spikes are likely to play significant roles in cortical information processing in awake animals (spatiotemporal binding, working memory) and during slow-wave sleep (neuronal Up states, consolidation of memories).
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Affiliation(s)
- Srdjan D Antic
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA.
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19
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Park S, Li C, Ames JB. Nuclear magnetic resonance structure of calcium-binding protein 1 in a Ca(2+) -bound closed state: implications for target recognition. Protein Sci 2011; 20:1356-66. [PMID: 21608059 DOI: 10.1002/pro.662] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 05/10/2011] [Indexed: 11/10/2022]
Abstract
Calcium-binding protein 1 (CaBP1), a neuron-specific member of the calmodulin (CaM) superfamily, regulates the Ca(2+) -dependent activity of inositol 1,4,5-triphosphate receptors (InsP3Rs) and various voltage-gated Ca(2+) channels. Here, we present the NMR structure of full-length CaBP1 with Ca(2+) bound at the first, third, and fourth EF-hands. A total of 1250 nuclear Overhauser effect distance measurements and 70 residual dipolar coupling restraints define the overall main chain structure with a root-mean-squared deviation of 0.54 Å (N-domain) and 0.48 Å (C-domain). The first 18 residues from the N-terminus in CaBP1 (located upstream of the first EF-hand) are structurally disordered and solvent exposed. The Ca(2+) -saturated CaBP1 structure contains two independent domains separated by a flexible central linker similar to that in calmodulin and troponin C. The N-domain structure of CaBP1 contains two EF-hands (EF1 and EF2), both in a closed conformation [interhelical angles = 129° (EF1) and 142° (EF2)]. The C-domain contains EF3 and EF4 in the familiar Ca(2+) -bound open conformation [interhelical angles = 105° (EF3) and 91° (EF4)]. Surprisingly, the N-domain adopts the same closed conformation in the presence or absence of Ca(2+) bound at EF1. The Ca(2+) -bound closed conformation of EF1 is reminiscent of Ca(2+) -bound EF-hands in a closed conformation found in cardiac troponin C and calpain. We propose that the Ca(2+) -bound closed conformation of EF1 in CaBP1 might undergo an induced-fit opening only in the presence of a specific target protein, and thus may help explain the highly specialized target binding by CaBP1.
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Affiliation(s)
- Saebomi Park
- Department of Chemistry, University of California, Davis, California 95616, USA
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20
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Guerra-Crespo M, Pérez-Monter C, Janga SC, Castillo-Ramírez S, Gutiérrez-Rios RM, Joseph-Bravo P, Pérez-Martínez L, Charli JL. Transcriptional profiling of fetal hypothalamic TRH neurons. BMC Genomics 2011; 12:222. [PMID: 21569245 PMCID: PMC3126781 DOI: 10.1186/1471-2164-12-222] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 05/10/2011] [Indexed: 01/08/2023] Open
Abstract
Background During murine hypothalamic development, different neuroendocrine cell phenotypes are generated in overlapping periods; this suggests that cell-type specific developmental programs operate to achieve complete maturation. A balance between programs that include cell proliferation, cell cycle withdrawal as well as epigenetic regulation of gene expression characterizes neurogenesis. Thyrotropin releasing hormone (TRH) is a peptide that regulates energy homeostasis and autonomic responses. To better understand the molecular mechanisms underlying TRH neuron development, we performed a genome wide study of its transcriptome during fetal hypothalamic development. Results In primary cultures, TRH cells constitute 2% of the total fetal hypothalamic cell population. To purify these cells, we took advantage of the fact that the segment spanning -774 to +84 bp of the Trh gene regulatory region confers specific expression of the green fluorescent protein (GFP) in the TRH cells. Transfected TRH cells were purified by fluorescence activated cell sorting, various cell preparations pooled, and their transcriptome compared to that of GFP- hypothalamic cells. TRH cells undergoing the terminal phase of differentiation, expressed genes implicated in protein biosynthesis, intracellular signaling and transcriptional control. Among the transcription-associated transcripts, we identified the transcription factors Klf4, Klf10 and Atf3, which were previously uncharacterized within the hypothalamus. Conclusion To our knowledge, this is one of the first reports identifying transcripts with a potentially important role during the development of a specific hypothalamic neuronal phenotype. This genome-scale study forms a rational foundation for identifying genes that might participate in the development and function of hypothalamic TRH neurons.
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Affiliation(s)
- Magdalena Guerra-Crespo
- Departamento de Genética y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Morelos
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Matta JA, Ashby MC, Sanz-Clemente A, Roche KW, Isaac JTR. mGluR5 and NMDA receptors drive the experience- and activity-dependent NMDA receptor NR2B to NR2A subunit switch. Neuron 2011; 70:339-51. [PMID: 21521618 PMCID: PMC3087383 DOI: 10.1016/j.neuron.2011.02.045] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2011] [Indexed: 11/30/2022]
Abstract
In cerebral cortex there is a developmental switch from NR2B- to NR2A-containing NMDA receptors (NMDARs) driven by activity and sensory experience. This subunit switch alters NMDAR function, influences synaptic plasticity, and its dysregulation is associated with neurological disorders. However, the mechanisms driving the subunit switch are not known. Here, we show in hippocampal CA1 pyramidal neurons that the NR2B to NR2A switch driven acutely by activity requires activation of NMDARs and mGluR5, involves PLC, Ca(2+) release from IP(3)R-dependent stores, and PKC activity. In mGluR5 knockout mice the developmental NR2B-NR2A switch in CA1 is deficient. Moreover, in visual cortex of mGluR5 knockout mice, the NR2B-NR2A switch evoked in vivo by visual experience is absent. Thus, we establish that mGluR5 and NMDARs are required for the activity-dependent NR2B-NR2A switch and play a critical role in experience-dependent regulation of NMDAR subunit composition in vivo.
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Affiliation(s)
- Jose A. Matta
- Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD20892, USA
| | - Michael C. Ashby
- Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD20892, USA
| | - Antonio Sanz-Clemente
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD20892, USA
| | - Katherine W. Roche
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD20892, USA
| | - John T. R. Isaac
- Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD20892, USA
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Michaelsen K, Lohmann C. Calcium dynamics at developing synapses: mechanisms and functions. Eur J Neurosci 2010; 32:218-23. [DOI: 10.1111/j.1460-9568.2010.07341.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Johnson HW, Schell MJ. Neuronal IP3 3-kinase is an F-actin-bundling protein: role in dendritic targeting and regulation of spine morphology. Mol Biol Cell 2010; 20:5166-80. [PMID: 19846664 DOI: 10.1091/mbc.e09-01-0083] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The actin microstructure in dendritic spines is involved in synaptic plasticity. Inositol trisphosphate 3-kinase A (ITPKA) terminates Ins(1,4,5)P(3) signals emanating from spines and also binds filamentous actin (F-actin) through its amino terminal region (amino acids 1-66, N66). Here we investigated how ITPKA, independent of its kinase activity, regulates dendritic spine F-actin microstructure. We show that the N66 region of the protein mediates F-actin bundling. An N66 fusion protein bundled F-actin in vitro, and the bundling involved N66 dimerization. By mutagenesis we identified a point mutation in a predicted helical region that eliminated both F-actin binding and bundling, rendering the enzyme cytosolic. A fusion protein containing a minimal helical region (amino acids 9-52, N9-52) bound F-actin in vitro and in cells, but had lower affinity. In hippocampal neurons, GFP-tagged N66 expression was highly polarized, with targeting of the enzyme predominantly to spines. By contrast, N9-52-GFP expression occurred in actin-rich structures in dendrites and growth cones. Expression of N66-GFP tripled the length of dendritic protrusions, induced longer dendritic spine necks, and induced polarized actin motility in time-lapse assays. These results suggest that, in addition to its ability to regulate intracellular Ca(2+) via Ins(1,4,5)P(3) metabolism, ITPKA regulates structural plasticity.
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Affiliation(s)
- Hong W Johnson
- Department of Pharmacology, Uniformed Services University, Bethesda, MD 20814, USA
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Oh MM, Oliveira FA, Disterhoft JF. Learning and aging related changes in intrinsic neuronal excitability. Front Aging Neurosci 2010; 2:2. [PMID: 20552042 PMCID: PMC2874400 DOI: 10.3389/neuro.24.002.2010] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 01/11/2010] [Indexed: 11/16/2022] Open
Abstract
A goal of many laboratories that study aging is to find a key cellular change(s) that can be manipulated and restored to a young-like state, and thus, reverse the age-related cognitive deficits. We have chosen to focus our efforts on the alteration of intrinsic excitability (as reflected by the postburst afterhyperpolarization, AHP) during the learning process in hippocampal pyramidal neurons. We have consistently found that the postburst AHP is significantly reduced in hippocampal pyramidal neurons from young adults that have successfully learned a hippocampus-dependent task. In the context of aging, the baseline intrinsic excitability of hippocampal neurons is decreased and therefore cognitive learning is impaired. In aging animals that are able to learn, neuron changes in excitability similar to those seen in young neurons during learning occur. Our challenge, then, is to understand how and why excitability changes occur in neurons from aging brains and cause age-associated learning impairments. After understanding the changes, we should be able to formulate strategies for reversing them, thus making old neurons function more as they did when they were young. Such a reversal should rescue the age-related cognitive deficits.
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Affiliation(s)
- M. Matthew Oh
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
| | - Fernando A. Oliveira
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
| | - John F. Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern UniversityChicago, IL, USA
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25
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Loebrich S, Nedivi E. The function of activity-regulated genes in the nervous system. Physiol Rev 2009; 89:1079-103. [PMID: 19789377 DOI: 10.1152/physrev.00013.2009] [Citation(s) in RCA: 175] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The mammalian brain is plastic in the sense that it shows a remarkable capacity for change throughout life. The contribution of neuronal activity to brain plasticity was first recognized in relation to critical periods of development, when manipulating the sensory environment was found to profoundly affect neuronal morphology and receptive field properties. Since then, a growing body of evidence has established that brain plasticity extends beyond development and is an inherent feature of adult brain function, spanning multiple domains, from learning and memory to adaptability of primary sensory maps. Here we discuss evolution of the current view that plasticity of the adult brain derives from dynamic tuning of transcriptional control mechanisms at the neuronal level, in response to external and internal stimuli. We then review the identification of "plasticity genes" regulated by changes in the levels of electrical activity, and how elucidating their cellular functions has revealed the intimate role transcriptional regulation plays in fundamental aspects of synaptic transmission and circuit plasticity that occur in the brain on an every day basis.
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Affiliation(s)
- Sven Loebrich
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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26
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Activity-dependent regulation of synapses by retrograde messengers. Neuron 2009; 63:154-70. [PMID: 19640475 DOI: 10.1016/j.neuron.2009.06.021] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/19/2009] [Accepted: 06/26/2009] [Indexed: 01/01/2023]
Abstract
Throughout the brain, postsynaptic neurons release substances from their cell bodies and dendrites that regulate the strength of the synapses they receive. Diverse chemical messengers have been implicated in retrograde signaling from postsynaptic neurons to presynaptic boutons. Here, we provide an overview of the signaling systems that lead to rapid changes in synaptic strength. We consider the capabilities, specializations, and physiological roles of each type of signaling system.
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27
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Deviant ryanodine receptor-mediated calcium release resets synaptic homeostasis in presymptomatic 3xTg-AD mice. J Neurosci 2009; 29:9458-70. [PMID: 19641109 DOI: 10.1523/jneurosci.2047-09.2009] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Presenilin mutations result in exaggerated endoplasmic reticulum (ER) calcium release in cellular and animal models of Alzheimer's disease (AD). In this study, we examined whether dysregulated ER calcium release in young 3xTg-AD neurons alters synaptic transmission and plasticity mechanisms before the onset of histopathology and cognitive deficits. Using electrophysiological recordings and two-photon calcium imaging in young (6-8 weeks old) 3xTg-AD and non-transgenic (NonTg) hippocampal slices, we show a marked increase in ryanodine receptor (RyR)-evoked calcium release within synapse-dense regions of CA1 pyramidal neurons. In addition, we uncovered a deviant contribution of presynaptic and postsynaptic ryanodine receptor-sensitive calcium stores to synaptic transmission and plasticity in 3xTg-AD mice that is not present in NonTg mice. As a possible underlying mechanism, the RyR2 isoform was found to be selectively increased more than fivefold in the hippocampus of 3xTg-AD mice relative to the NonTg controls. These novel findings demonstrate that 3xTg-AD CA1 neurons at presymptomatic ages operate under an aberrant, yet seemingly functional, calcium signaling and synaptic transmission system long before AD histopathology onset. These early signaling alterations may underlie the later synaptic breakdown and cognitive deficits characteristic of later stage AD.
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28
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Paspalas CD, Selemon LD, Arnsten AFT. Mapping the regulator of G protein signaling 4 (RGS4): presynaptic and postsynaptic substrates for neuroregulation in prefrontal cortex. ACTA ACUST UNITED AC 2009; 19:2145-55. [PMID: 19153107 DOI: 10.1093/cercor/bhn235] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Regulator of G protein signaling 4 (RGS4) regulates intracellular signaling via G proteins and is markedly reduced in the prefrontal cortex (PFC) of patients with schizophrenia. Characterizing the expression of RGS4 within individual neuronal compartments is thus key to understanding its actions on individual G protein-coupled receptors (GPCRs). Here we present an ultrastructural reference map of RGS4 protein in macaque PFC based on immunogold electron microscopic analysis. At the soma, all labeling was asynaptic and affiliated with subsurface cistern microdomains of pyramidal neurons. The nucleus displayed most of immunoreactivity. RGS4 levels were particularly high along proximal apical dendrites and markedly decreased with distance from the soma; clustered label was present at the bifurcation into second-order branches. In distal dendrites and in spines, the protein was found flanking or directly facing the postsynaptic density of symmetric and asymmetric synapses. Axons also expressed RGS4. In fact, the density and distribution of pre- and postsynaptic labeling was correlated with the axon ultrastructure and the type of established synapses. The data indicate that RGS4 is strategically positioned to regulate not only postsynaptic but also presynaptic signaling in response to synaptic and nonsynaptic GPCR activation, having broad yet highly selective influences on multiple aspects of PFC cellular physiology.
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29
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Long-term potentiation selectively expressed by NMDA receptors at hippocampal mossy fiber synapses. Neuron 2008; 57:108-20. [PMID: 18184568 DOI: 10.1016/j.neuron.2007.11.024] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 09/28/2007] [Accepted: 11/21/2007] [Indexed: 11/20/2022]
Abstract
The mossy fiber to CA3 pyramidal cell synapse (mf-CA3) provides a major source of excitation to the hippocampus. Thus far, these glutamatergic synapses are well recognized for showing a presynaptic, NMDA receptor-independent form of LTP that is expressed as a long-lasting increase of transmitter release. Here, we show that in addition to this "classical" LTP, mf-CA3 synapses can undergo a form of LTP characterized by a selective enhancement of NMDA receptor-mediated transmission. This potentiation requires coactivation of NMDA and mGlu5 receptors and a postsynaptic calcium rise. Unlike classical LTP, expression of this mossy fiber LTP is due to a PKC-dependent recruitment of NMDA receptors specifically to the mf-CA3 synapse via a SNARE-dependent process. Having two mechanistically different forms of LTP may allow mf-CA3 synapses to respond with more flexibility to the changing demands of the hippocampal network.
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30
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Spruston N. Pyramidal neurons: dendritic structure and synaptic integration. Nat Rev Neurosci 2008; 9:206-21. [PMID: 18270515 DOI: 10.1038/nrn2286] [Citation(s) in RCA: 1040] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pyramidal neurons are characterized by their distinct apical and basal dendritic trees and the pyramidal shape of their soma. They are found in several regions of the CNS and, although the reasons for their abundance remain unclear, functional studies--especially of CA1 hippocampal and layer V neocortical pyramidal neurons--have offered insights into the functions of their unique cellular architecture. Pyramidal neurons are not all identical, but some shared functional principles can be identified. In particular, the existence of dendritic domains with distinct synaptic inputs, excitability, modulation and plasticity appears to be a common feature that allows synapses throughout the dendritic tree to contribute to action-potential generation. These properties support a variety of coincidence-detection mechanisms, which are likely to be crucial for synaptic integration and plasticity.
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Affiliation(s)
- Nelson Spruston
- Northwestern University, Department of Neurobiology & Physiology, 2205 Tech Drive, Evanston, Illinois 60208, USA.
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31
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Power JM, Sah P. Competition between calcium-activated K+ channels determines cholinergic action on firing properties of basolateral amygdala projection neurons. J Neurosci 2008; 28:3209-20. [PMID: 18354024 PMCID: PMC6670694 DOI: 10.1523/jneurosci.4310-07.2008] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 02/04/2008] [Accepted: 02/11/2008] [Indexed: 11/21/2022] Open
Abstract
Acetylcholine (ACh) is an important modulator of learning, memory, and synaptic plasticity in the basolateral amygdala (BLA) and other brain regions. Activation of muscarinic acetylcholine receptors (mAChRs) suppresses a variety of potassium currents, including sI(AHP), the calcium-activated potassium conductance primarily responsible for the slow afterhyperpolarization (AHP) that follows a train of action potentials. Muscarinic stimulation also produces inositol 1,4,5-trisphosphate (IP(3)), releasing calcium from intracellular stores. Here, we show using whole-cell patch-clamp recordings and high-speed fluorescence imaging that focal application of mAChR agonists evokes large rises in cytosolic calcium in the soma and proximal dendrites in rat BLA projection neurons that are often associated with activation of an outward current that hyperpolarizes the cell. This hyperpolarization results from activation of small conductance calcium-activated potassium (SK) channels, secondary to the release of calcium from intracellular stores. Unlike bath application of cholinergic agonists, which always suppressed the AHP, focal application of ACh often evoked a paradoxical enhancement of the AHP and spike-frequency adaptation. This enhancement was correlated with amplification of the action potential-evoked calcium response and resulted from the activation of SK channels. When SK channels were blocked, cholinergic stimulation always reduced the AHP and spike-frequency adaptation. Conversely, suppression of the sI(AHP) by the beta-adrenoreceptor agonist, isoprenaline, potentiated the cholinergic enhancement of the AHP. These results suggest that competition between cholinergic suppression of the sI(AHP) and cholinergic activation of the SK channels shapes the AHP and spike-frequency adaptation.
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Affiliation(s)
- John M. Power
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland 4072, Australia
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32
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Peercy BE. Initiation and propagation of a neuronal intracellular calcium wave. J Comput Neurosci 2008; 25:334-48. [PMID: 18320300 DOI: 10.1007/s10827-008-0082-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 01/16/2008] [Accepted: 01/25/2008] [Indexed: 10/22/2022]
Abstract
The ability to image calcium movement within individual neurons inspires questions of functionality including whether calcium entry into the nucleus is related to genetic regulation for phenomena such as long term potentiation. Calcium waves have been initiated in hippocampal pyramidal cells with glutmatergic signals both in the presence and absence of back propagating action potentials (BPAPs). The dendritic sites of initiation of these calcium waves within about 100 microm of the soma are thought to be localized near oblique junctions. Stimulation of synapses on oblique dendrites leads to production of inositol 1,4,5-trisphosphate (IP(3)) which diffuses to the apical dendrite igniting awaiting IP(3) receptors (IP(3)Rs) and initiating and propagating catalytic calcium release from the endoplasmic reticulum. We construct a reduced mathematical system which accounts for calcium wave initiation and propagation due to elevated IP(3). Inhomogeneity in IP(3) distribution is responsible for calcium wave initiation versus subthreshold or spatially uniform suprathreshold activation. However, the likelihood that a calcium wave is initiated does not necessarily increase with more calcium entering from BPAPs. For low transient synaptic stimuli, timing between IP(3) generation and BPAPs is critical for calcium wave initiation. We also show that inhomogeneity in IP(3)R density can account for calcium wave directionality. Simulating somatic muscarinic receptor production of IP(3), we can account for the critical difference between calcium wave entry into the soma and failure to do so.
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Affiliation(s)
- Bradford E Peercy
- Laboratory of Biological Modeling/NIDDK/NIH, Bldg. 12A, Rm 4007, MSC 5621, South Dr., Bethesda, MD 20892-5621, USA.
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33
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Abstract
Spatiotemporal activity patterns in local neural networks are fundamental to brain function. Network activity can now be measured in vivo using two-photon imaging of cell populations that are labeled with fluorescent calcium indicators. In this review, we discuss basic aspects of in vivo calcium imaging and highlight recent developments that will help to uncover operating principles of neural circuits.
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Affiliation(s)
- Werner Göbel
- Department of Neurophysiology, Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Fritjof Helmchen
- Department of Neurophysiology, Brain Research Institute, University of Zurich, Zurich, Switzerland
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34
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Abstract
Imaging technologies are well suited to study neuronal dendrites, which are key elements for synaptic integration in the CNS. Dendrites are, however, frequently oriented perpendicular to tissue surfaces, impeding in vivo imaging approaches. Here we introduce novel laser-scanning modes for two-photon microscopy that enable in vivo imaging of spatiotemporal activity patterns in dendrites. First, we developed a method to image planes arbitrarily oriented in 3D, which proved particularly beneficial for calcium imaging of parallel fibers and Purkinje cell dendrites in rat cerebellar cortex. Second, we applied free linescans—either through multiple dendrites or along a single vertically oriented dendrite—to reveal fast dendritic calcium dynamics in neocortical pyramidal neurons. Finally, we invented a ribbon-type 3D scanning method for imaging user-defined convoluted planes enabling simultaneous measurements of calcium signals along multiple apical dendrites. These novel scanning modes will facilitate optical probing of dendritic function in vivo.
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Affiliation(s)
- Werner Göbel
- Department of Neurophysiology, Brain Research Institute, Winterthurerstr 190, CH-8057, Zurich, Switzerland
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35
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Samways DSK, Egan TM. Acidic amino acids impart enhanced Ca2+ permeability and flux in two members of the ATP-gated P2X receptor family. ACTA ACUST UNITED AC 2007; 129:245-56. [PMID: 17325195 PMCID: PMC2151611 DOI: 10.1085/jgp.200609677] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
P2X receptors are ATP-gated cation channels expressed in nerve, muscle, bone, glands, and the immune system. The seven family members display variable Ca2+ permeabilities that are amongst the highest of all ligand-gated channels (Egan and Khakh, 2004). We previously reported that polar residues regulate the Ca2+ permeability of the P2X2 receptor (Migita et al., 2001). Here, we test the hypothesis that the formal charge of acidic amino acids underlies the higher fractional Ca2+ currents (Pf%) of the rat and human P2X1 and P2X4 subtypes. We used patch-clamp photometry to measure the Pf% of HEK-293 cells transiently expressing a range of wild-type and genetically altered receptors. Lowering the pH of the extracellular solution reduced the higher Pf% of the P2X1 receptor but had no effect on the lower Pf% of the P2X2 receptor, suggesting that ionized side chains regulate the Ca2+ flux of some family members. Removing the fixed negative charges found at the extracellular ends of the transmembrane domains also reduced the higher Pf% of P2X1 and P2X4 receptors, and introducing these charges at homologous positions increased the lower Pf% of the P2X2 receptor. Taken together, the data suggest that COO− side chains provide an electrostatic force that interacts with Ca2+ in the mouth of the pore. Surprisingly, the glutamate residue that is partly responsible for the higher Pf% of the P2X1 and P2X4 receptors is conserved in the P2X3 receptor that has the lowest Pf% of all family members. We found that neutralizing an upstream His45 increased Pf% of the P2X3 channel, suggesting that this positive charge masks the facilitation of Ca2+ flux by the neighboring Glu46. The data support the hypothesis that formal charges near the extracellular ends of transmembrane domains contribute to the high Ca2+ permeability and flux of some P2X receptors.
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Affiliation(s)
- Damien S K Samways
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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36
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Jasoni CL, Todman MG, Strumia MM, Herbison AE. Cell type-specific expression of a genetically encoded calcium indicator reveals intrinsic calcium oscillations in adult gonadotropin-releasing hormone neurons. J Neurosci 2007; 27:860-7. [PMID: 17251427 PMCID: PMC6101190 DOI: 10.1523/jneurosci.3579-06.2007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The gonadotropin-releasing hormone (GnRH) neurons exhibit a unique pattern of episodic activity to control fertility in all mammals. To enable the measurement of intracellular calcium concentration ([Ca2+]i) in adult GnRH neurons in situ, we generated transgenic mice in which the genetically encodable calcium indicator ratiometric Pericam was expressed by approximately 95% of GnRH neurons. Real-time monitoring of [Ca2+]i within adult male GnRH neurons in the acute brain slice revealed that approximately 70% of GnRH neurons exhibited spontaneous, 10-15 s duration [Ca2+]i transients with a mean frequency of 7 per hour. The remaining 30% of GnRH neurons did not exhibit calcium transients nor did a population of non-GnRH cells located within the lateral septum that express Pericam. Pharmacological studies using antagonists to the inositol-1,4,5-trisphosphate receptor (InsP3R) and several calcium channels, demonstrated that [Ca2+]i transients in GnRH neurons were generated by an InsP3R-dependent store-release mechanism and were independent of plasma membrane ligand- or voltage-gated calcium channels. Interestingly, the abolition of action potential-mediated transmission with tetrodotoxin reduced the number of [Ca2+]i transients in GnRH neurons by 50% (p < 0.05), suggesting a modulatory role for synaptic inputs on [Ca2+]i transient frequency. Using a novel transgenic strategy that enables [Ca2+]i to be examined in a specific neuronal phenotype in situ, we provide evidence for spontaneous [Ca2+]i fluctuations in adult GnRH neurons. This represents the initial description of spontaneous [Ca2+]i transients in mature neurons and shows that they arise from an InsP3R-generating mechanism that is further modulated by synaptic inputs.
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Affiliation(s)
| | | | - Max M. Strumia
- Department of Mathematics, University of Otago School of Medical Sciences, Dunedin 9054, New Zealand
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37
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Power JM, Sah P. Distribution of IP3-mediated calcium responses and their role in nuclear signalling in rat basolateral amygdala neurons. J Physiol 2007; 580:835-57. [PMID: 17303640 PMCID: PMC2075466 DOI: 10.1113/jphysiol.2006.125062] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Metabotropic receptor activation is important for learning, memory and synaptic plasticity in the amygdala and other brain regions. Synaptic stimulation of metabotropic receptors in basolateral amygdala (BLA) projection neurons evokes a focal rise in free Ca(2+) in the dendrites that propagate as waves into the soma and nucleus. These Ca(2+) waves initiate in the proximal dendrites and show limited propagation centrifugally away from the soma. In other cell types, Ca(2+) waves have been shown to be mediated by either metabotropic glutamate receptor (mGluR) or muscarinic receptor (mAChR) activation. Here we show that mGluRs and mAChRs act cooperatively to release Ca(2+) from inositol 1,4,5-trisphosphate (IP(3))-sensitive intracellular Ca(2+) stores. Whereas action potentials (APs) alone were relatively ineffective in raising nuclear Ca(2+), their pairing with metabotropic receptor activation evoked an IP(3)-receptor-mediated Ca(2+)-induced Ca(2+) release, raising nuclear Ca(2+) into the micromolar range. Metabotropic-receptor-mediated Ca(2+)-store release was highly compartmentalized. When coupled with metabotropic receptor stimulation, large robust Ca(2+) rises and AP-induced amplification were observed in the soma, nucleus and sparsely spiny dendritic segments with metabotropic stimulation. In contrast, no significant amplification of the Ca(2+) transient was detected in spine-dense high-order dendritic segments. Ca(2+) rises evoked by photolytic uncaging of IP(3) showed the same distribution, suggesting that IP(3)-sensitive Ca(2+) stores are preferentially located in the soma and proximal dendrites. This distribution of metabotropic-mediated store release suggests that the neuromodulatory role of metabotropic receptor stimulation in BLA-dependent learning may result from enhanced nuclear signalling.
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Affiliation(s)
- John M Power
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland 4072, Australia
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38
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Rabinowitch I, Segev I. The endurance and selectivity of spatial patterns of long-term potentiation/depression in dendrites under homeostatic synaptic plasticity. J Neurosci 2007; 26:13474-84. [PMID: 17192430 PMCID: PMC6674716 DOI: 10.1523/jneurosci.4333-06.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We investigated analytically and numerically the interplay between two opposing forms of synaptic plasticity: positive-feedback, long-term potentiation/depression (LTP/LTD), and negative-feedback, homeostatic synaptic plasticity (HSP). A detailed model of a CA1 pyramidal neuron, with numerous HSP-modifiable dendritic synapses, demonstrates that HSP may have an important role in selecting which spatial patterns of LTP/LTD are to last. Several measures are developed for predicting the net residual potentiation/depression after HSP from the initial spatial pattern of LTP/LTD. Under a local dendritic HSP mechanism, sparse patterns of LTP/LTD, which we show, using information theoretical tools, to have a significant impact on the output of the postsynaptic neuron, will persist. In contrast, spatially clustered patterns with a smaller impact on the output will diminish. A global somatic HSP mechanism, conversely, will favor distally occurring LTP/LTDs over proximal ones. Despite the negative-feedback nature of HSP, under both local and global HSP, numerous synaptic potentiations/depressions can persist. These experimentally testable results imply that HSP could be significantly involved in shaping the spatial distribution of synaptic weights in the dendrites and not just normalizing it, as is currently believed.
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Affiliation(s)
- Ithai Rabinowitch
- Interdisciplinary Center for Neural Computation and the Department of Neurobiology, Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Idan Segev
- Interdisciplinary Center for Neural Computation and the Department of Neurobiology, Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond Safra Campus, Givat Ram, Jerusalem, 91904, Israel
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39
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Hammond GRV, Schiavo G. Polyphosphoinositol lipids: Under-PPInning synaptic function in health and disease. Dev Neurobiol 2007; 67:1232-47. [PMID: 17514716 DOI: 10.1002/dneu.20509] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Phosphoinositides (PPIn) form a unique family of lipids derived by phosphorylation of the parent compound, phosphatidylinositol. Despite being minor constituents of synaptic membranes, these lipids have exceptionally high rates of metabolic turnover and are involved with myriad aspects of pre- and post-synaptic function, from the control of the synaptic vesicle cycle to postsynaptic excitability. In this review, we outline the main synaptic processes known to be regulated by these molecules, focusing mainly but not exclusively on the major species phosphatidylinositol 4-phosphate and phosphatidylinositol (4,5)-bisphosphate. Furthermore, we discuss the enzymes responsible for their synthesis and degradation, with a view to exploring how the activity-dependent control of their enzymatic action can lead to the precise regulation of PPIn levels at the nerve terminal. Also, the modulation of synaptic PPIn turnover by drugs used for the treatment of bipolar disorder is discussed. We propose that the modulation of PPIn levels may act as a central mechanism to coordinate the cascade of synaptic events leading to neurotransmission.
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Affiliation(s)
- Gerald R V Hammond
- Molecular NeuroPathobiology, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3PX, United Kingdom.
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40
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Lively S, Ringuette MJ, Brown IR. Localization of the extracellular matrix protein SC1 to synapses in the adult rat brain. Neurochem Res 2006; 32:65-71. [PMID: 17151913 DOI: 10.1007/s11064-006-9226-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
Extracellular matrix molecules play important roles in neural developmental processes such as axon guidance and synaptogenesis. When development is complete, many of these molecules are down-regulated, however the molecules that remain highly expressed are often involved in modulation of synaptic function. SC1 is an example of an extracellular matrix protein whose expression remains high in the adult rat brain. Confocal microscopy revealed that SC1 demonstrates a punctate pattern in synaptic enriched regions of the cerebral cortex and cerebellum. Higher resolution analysis using electron microscopy indicated that SC1 localizes to synapses, particularly the postsynaptic terminal. SC1 was also detected in perisynaptic glial processes that envelop synapses.
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Affiliation(s)
- Starlee Lively
- Center for the Neurobiology of Stress, University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4
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41
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Korkotian E, Segal M. Spatially confined diffusion of calcium in dendrites of hippocampal neurons revealed by flash photolysis of caged calcium. Cell Calcium 2006; 40:441-9. [PMID: 17064764 DOI: 10.1016/j.ceca.2006.08.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Accepted: 08/23/2006] [Indexed: 11/19/2022]
Abstract
The extent of diffusion of a locally evoked calcium surge in dendrites of cultured hippocampal neurons was studied by flash photolysis of caged EGTA. Cells were transfected with pDsRed for visualization, preincubated with caged NP-EGTA (AM) and Fluo-4 (AM) at room temperature and imaged in a PASCAL confocal microscope. Pulses of UV laser light within an active sphere of about 1 micro m(2) produced a rise of Fluo-4 fluorescence transients in dendrites which peaked at 1 ms and decayed exponentially with a fast (8-10 ms) time constant. A slower decay component was uncovered following incubation with thapsigargin. Lateral diffusion of [Ca(2+)]i did not vary significantly among different size dendrites being symmetric and reaching about 3-3.5 micro mm at a diffusion rate of 0.8 micro mm/ms on both sides of the photolysis center. Fluo-4 was also replaced by the membrane-bound Fluo-NOMO (AM) or by the 'heavy' Calcium Green dextran (CGd) loaded through a patch pipette. Similar rates of diffusion were found in these cases, indicating that the diffusion is not of the dye complexed to calcium but of genuine free calcium ions. Interestingly, presence of a dendritic spine at the focus of photolysis significantly reduced [Ca(2+)]i spread while the focal transient remained unaffected. Finally, [Ca(2+)]i diffused about twice as far from the photolysis sphere in glass tubes of a similar diameter to that of a dendrite, indicating that intrinsic calcium uptake mechanisms in the dendrite determine the diffusion of calcium away from its original site of rise.
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Affiliation(s)
- Eduard Korkotian
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel.
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42
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Ming Y, Zhang H, Long L, Wang F, Chen J, Zhen X. Modulation of Ca2+ signals by phosphatidylinositol-linked novel D1 dopamine receptor in hippocampal neurons. J Neurochem 2006; 98:1316-23. [PMID: 16771826 DOI: 10.1111/j.1471-4159.2006.03961.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent evidence indicates the existence of a putative novel phosphatidylinositol-linked D1 dopamine receptor in brain that mediates phosphatidylinositol hydrolysis via activation of phospholipase Cbeta. The present work was designed to characterize the Ca(2+) signals regulated by this phosphatidylinositol-linked D(1) dopamine receptor in primary cultures of hippocampal neurons. The results indicated that stimulation of phosphatidylinositol-linked D1 dopamine receptor by its newly identified selective agonist SKF83959 induced a long-lasting increase in basal [Ca(2+)](i) in a time- and dose-dependent manner. Stimulation was observable at 0.1 microm and reached the maximal effect at 30 microm. The [Ca(2+)](i) increase induced by 1 microm SKF83959 reached a plateau in 5 +/- 2.13 min, an average 96 +/- 5.6% increase over control. The sustained elevation of [Ca(2+)](i) was due to both intracellular calcium release and calcium influx. The initial component of Ca(2+) increase through release from intracellular stores was necessary for triggering the late component of Ca(2+) rise through influx. We further demonstrated that activation of phospholipase Cbeta/inositol triphosphate was responsible for SKF83959-induced Ca(2+) release from intracellular stores. Moreover, inhibition of voltage-operated calcium channel or NMDA receptor-gated calcium channel strongly attenuated SKF83959-induced Ca(2+) influx, indicating that both voltage-operated calcium channel and NMDA receptor contribute to phosphatidylinositol-linked D(1) receptor regulation of [Ca(2+)](i).
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Animals, Newborn/physiology
- Calcium/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Signaling/physiology
- Cells, Cultured
- Dopamine Agonists/pharmacology
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Hippocampus/cytology
- Hippocampus/physiology
- Isoenzymes/metabolism
- Neurons/physiology
- Phosphatidylinositols/physiology
- Phospholipase C beta
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/physiology
- Second Messenger Systems/physiology
- Thapsigargin/pharmacology
- Type C Phospholipases/metabolism
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Affiliation(s)
- Yuling Ming
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, HUST, Wuhan, China
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Maggio N, Segal M. Unique regulation of long term potentiation in the rat ventral hippocampus. Hippocampus 2006; 17:10-25. [PMID: 17094146 DOI: 10.1002/hipo.20237] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Morphological and electrophysiological evidence has been accumulated in recent years to indicate that a functional gradient exists along the septo-temporal axis of the hippocampus such that spatial memory is associated primarily with the dorsal (septal) sector while the functions of the ventral sector are not yet clearly defined. Also, the ventral hippocampus (VH) is reported to express a much smaller long term potentiation of responses to afferent stimulation than the dorsal sector. In the present study, we first confirmed that CA1 region of VH slices expresses significantly smaller LTP than the dorsal hippocampus. Strikingly, much larger LTP was obtained in VH slices following low frequency priming stimulation applied prior to the tetanic stimulation. DHPG ((S)-3,5-Dihydroxyphenylglycine hydrate) a metabotropic glutamate receptor agonist, produced a similar potentiating effect on LTP as that produced by the priming stimulation. In both cases, the spectral analysis of spontaneous electrical activity recorded from the same location in the slice revealed an increase in peak amplitude around 30 Hz. MCPG, a metabotropic glutamate receptor antagonist, and both thapsigargin and cyclopiazonic acid, inhibitors of Ca(2+) release from stores, blocked the potentiating action of both DHPG and the priming stimulation. These results indicate that the ventral hippocampus possesses different network properties compared to the dorsal hippocampus and that its ability to undergo plastic changes is controlled by a metabotropic glutamate receptor.
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Affiliation(s)
- Nicola Maggio
- Department of Neurobiology, The Weizmann Institute, Rehovot, Israel
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