Homeostatic plasticity in hippocampal slice cultures involves changes in voltage-gated Na+ channel expression

Neurons preserve stable electrophysiological properties despite ongoing changes in morphology and connectivity throughout their lifetime. This dynamic compensatory adjustment, termed 'homeostatic plasticity', may be a fundamental means by which the brain normalizes its excitability, and is possibly altered in disease states such as epilepsy. Despite this significance, the cellular mechanisms of homeostatic plasticity are incompletely understood. Using field potential analyses, we observed a compensatory enhancement of neural excitability after 48 h of activity deprivation via tetrodotoxin (TTX) in hippocampal slice cultures. Because activity deprivation can enhance voltage-gated sodium channel (VGSC) currents, we used Western blot analyses to probe for these channels in control and activity-deprived slice cultures. A significant upregulation of VGSCs expression was evident after activity deprivation. Furthermore, immunohistochemistry revealed this upregulation to occur along primarily pyramidal cell dendrites. Western blot analyses of cultures after 1 day of recovery from activity deprivation showed that VGSC levels returned to control levels, indicating that multiple molecular mechanisms contribute to enhanced excitability. Because of their longevity and in vivo-like cytoarchitecture, we conclude that slice cultures may be highly useful for investigating homeostatic plasticity. Furthermore, we demonstrate that enhanced excitability involves changes in channel expression with a targeted localization likely profound transform the integrative capacities of hippocampal pyramidal cells and their dendrites.

[1]  M. Beal.  Role of excitotoxicity in human neurological disease , 1992, Current Opinion in Neurobiology.

[2]  B. Bahr,et al.  Stable maintenance of glutamate receptors and other synaptic components in long‐term hippocampal slices , 1995, Hippocampus.

[3]  D. Debanne,et al.  Organotypic slice cultures: a technique has come of age , 1997, Trends in Neurosciences.

[4]  K. Rhodes,et al.  Type I and type II Na+ channel α‐subunit polypeptides exhibit distinct spatial and temporal patterning, and association with auxiliary subunits in rat brain , 1999, The Journal of comparative neurology.

[5]  G. Alcaraz,et al.  Multiple pathways regulate the expression of genes encoding sodium channel subunits in developing neurons. , 1998, Brain research. Molecular brain research.

[6]  E. J. Green,et al.  Altered synaptic transmission in dentate gyrus of rats reared in complex environments: evidence from hippocampal slices maintained in vitro. , 1986, Journal of neurophysiology.

[7]  R. Malenka,et al.  AMPA receptor trafficking and synaptic plasticity. , 2002, Annual review of neuroscience.

[8]  M. Frotscher,et al.  Blockade of neuronal activity alters spine maturation of dentate granule cells but not their dendritic arborization , 1999, Neuroscience.

[9]  P. E. Kunkler,et al.  Reactive Astrocytosis from Excitotoxic Injury in Hippocampal Organ Culture Parallels that Seen in Vivo , 1997, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[10]  H. Duff,et al.  Upregulation of the rat cardiac sodium channel by in vivo treatment with a class I antiarrhythmic drug. , 1991, The Journal of clinical investigation.

[11]  J. Hinds,et al.  Neurogenesis in the adult rat: electron microscopic analysis of light radioautographs. , 1977, Science.

[12]  A Goldbeter,et al.  Protein phosphorylation driven by intracellular calcium oscillations: a kinetic analysis. , 1992, Biophysical chemistry.

[13]  Niraj S. Desai,et al.  Activity-dependent scaling of quantal amplitude in neocortical neurons , 1998, Nature.

[14]  D Debanne,et al.  Physiology and pharmacology of unitary synaptic connections between pairs of cells in areas CA3 and CA1 of rat hippocampal slice cultures. , 1995, Journal of neurophysiology.

[15]  V. Murthy,et al.  Multiple forms of synaptic plasticity triggered by selective suppression of activity in individual neurons , 2002, Nature.

[16]  P. E. Kunkler,et al.  Calcium Waves Precede Electrophysiological Changes of Spreading Depression in Hippocampal Organ Cultures , 1998, The Journal of Neuroscience.

[17]  KM Harris,et al.  Three-dimensional structure of dendritic spines and synapses in rat hippocampus (CA1) at postnatal day 15 and adult ages: implications for the maturation of synaptic physiology and long-term potentiation [published erratum appears in J Neurosci 1992 Aug;12(8):following table of contents] , 1992, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[18]  Niraj S. Desai,et al.  Critical periods for experience-dependent synaptic scaling in visual cortex , 2002, Nature Neuroscience.

[19]  Kristen M. Harris,et al.  Erratum: Three-dimensional structure of dendritic spines and synapses in rat hippocampus (CA1) at postnatal day 15 and adult ages: Implications for the maturation of synaptic physiology and long-term potentiation (J Neurosci (July 1992) 12 (2685-2705)) , 1992 .

[20]  J. Kleim,et al.  A brain adaptation view of plasticity: is synaptic plasticity an overly limited concept? , 2002, Progress in brain research.

[21]  K. Kaila,et al.  Post-insult activity is a major cause of delayed neuronal death in organotypic hippocampal slices exposed to glutamate , 2001, Neuroscience.

[22]  G. Davis,et al.  Maintaining the stability of neural function: a homeostatic hypothesis. , 2001, Annual review of physiology.

[23]  J. Trimmer,et al.  Dependence of Nodal Sodium Channel Clustering on Paranodal Axoglial Contact in the Developing CNS , 1999, The Journal of Neuroscience.

[24]  T. Ishikawa,et al.  Time Course of Brain Neuronal Degeneration and Heat Shock Protein (72) Expression Following Neck Tourniquet-Induced Cerebral Ischemia in the Rat , 2000, Cellular and Molecular Neurobiology.

[25]  Effects of ethanol on voltage-sensitive Na-channels in cultured skeletal muscle: up-regulation as a result of chronic treatment. , 1990, The Journal of pharmacology and experimental therapeutics.

[26]  B. Gähwiler,et al.  Cellular and connective organization of slice cultures of the rat hippocampus and fascia dentata , 1984, The Journal of comparative neurology.

[27]  Bruce R. Johnson,et al.  Activity-Independent Homeostasis in Rhythmically Active Neurons , 2003, Neuron.

[28]  M. Ehlers.  Activity level controls postsynaptic composition and signaling via the ubiquitin-proteasome system , 2003, Nature Neuroscience.

[29]  B. Gähwiler,et al.  Anatomical and Physiological Properties of GABAergic Neurotransmission in Organotypic Slice Cultures of Rat Hippocampus , 1989, The European journal of neuroscience.

[30]  U. Staubli,et al.  Studies on Long-Term Depression in Area CA1 of the Anesthetized and Freely Moving Rat , 1997, The Journal of Neuroscience.

[31]  Niraj S. Desai,et al.  Plasticity in the intrinsic excitability of cortical pyramidal neurons , 1999, Nature Neuroscience.

[32]  T. Sakaguchi,et al.  Dual mode ofN-methyl-d-aspartate-induced neuronal death in hippocampal slice cultures in relation toN-methyl-d-aspartate receptor properties , 1997, Neuroscience.

[33]  D. Muller,et al.  A simple method for organotypic cultures of nervous tissue , 1991, Journal of Neuroscience Methods.

[34]  Marco Capogna,et al.  Miniature synaptic events maintain dendritic spines via AMPA receptor activation , 1999, Nature Neuroscience.

[35]  K. Holthoff,et al.  A problem with Hebb and local spikes , 2002, Trends in Neurosciences.

[36]  B. Kristensen,et al.  Comparison of excitotoxic profiles of ATPA, AMPA, KA and NMDA in organotypic hippocampal slice cultures , 2001, Brain Research.

[37]  H. Yokoo,et al.  Regulation of Voltage‐Dependent Sodium Channel Expression in Adrenal Chromaffin Cells , 2002, Annals of the New York Academy of Sciences.

[38]  S. Waxman,et al.  Type III sodium channel mRNA is expressed in embryonic but not adult spinal sensory neurons, and is reexpressed following axotomy. , 1994, Journal of neurophysiology.

[39]  M. Kreutz,et al.  Apoptotic versus necrotic characteristics of retinal ganglion cell death after partial optic nerve injury. , 1999, Journal of neurotrauma.

[40]  B. Bahr,et al.  Long‐term hippocampal slices: A model system for investigating synaptic mechanisms and pathologic processes , 1995, Journal of neuroscience research.

[41]  R. Gutiérrez,et al.  Synaptic reorganization in explanted cultures of rat hippocampus , 1999, Brain Research.

[42]  K. Svoboda,et al.  Rapid spine delivery and redistribution of AMPA receptors after synaptic NMDA receptor activation. , 1999, Science.

[43]  S. Nelson,et al.  Hebb and homeostasis in neuronal plasticity , 2000, Current Opinion in Neurobiology.

[44]  William J Tyler,et al.  Miniature synaptic transmission and BDNF modulate dendritic spine growth and form in rat CA1 neurones , 2003, The Journal of physiology.

[45]  P. Bergold,et al.  Excitatory and inhibitory pathways modulate kainate excitotoxicity in hippocampal slice cultures , 1993, Neuroscience Letters.