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2003 Fiscal Year Final Research Report Summary

Molecular coupling required for intracellular calcium release that regulates synaptic depression

Research Project

Project/Area Number 13480266
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Neuroscience in general
Research InstitutionKyoto University

Principal Investigator

KATO Nobuo  Kyoto University, Graduate School of Medicine, Associate Professor, 医学研究科, 助教授 (10152729)

Co-Investigator(Kenkyū-buntansha) SUGIURA Shigeki  Nara Medical University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (40179130)
Project Period (FY) 2001 – 2003
KeywordsCalcium release / Calcium channel / Synaptic plasticity / Synaptic depression / Hippocampus CA1 / Synaptic transmission
Research Abstract

Induction of synaptic plasticity, such as long-term potentiation (LTP) and long-term depression (LTD), is believed to require synaptically induced Ca2+ rises. Although LTP is thought to be induced by large rises of Ca2+, two different mechanisms have been proposed for LTD induction : one is LTD induction by intracellular Ca2+ release, whereas the other mechanism depends on moderate rises of Ca2+ from whatever calcium sources. We studied whether both of these LTD induction mechanisms operate and, if so, how these mechanisms cooperate. Under pharmacological manipulations, LTD induction was attempted by using conditioning stimulations of different frequencies, and relationship were seeked for between the magnitude of LTD and the extent of intracellular Ca2+ rises. With 0.5-1.0 Hz stimulation, LTD induction depends crucially on the calcium source but not on the amount of calcium rise, and calcium release facilitated LTD induction with calcium influx via L-type calcium channel inhibiting it … More . At 0.5 Hz, a ryanodine receptor agonist, caffeine, and an L-type Ca2+ channel blocker, nifedipine, both enhanced the magnitude of LTD. At 1Hz, an internal Ca2+ stone depletor, thapsigargin and an L-type Ca2+ channel activator, S (-)-BAY K8644, both decreased LTD magnitude. At 2Hz, however, the change in synaptic efficiency was in parallel with the amount of Ca2+ rises. From these findings, we conclude that the two mechanisms are both involved in LTD induction but separately at two different levels of postsynaptic activation : the source dependent mechanism operate at lower postspaptic activation ranges than the calcium concentration dependent mechanism does. Relationship between LTD induction mechanisms detailed above and the novel calcium release mechanisms that we have observed (IP3-assisted CICR) has also been investigated. The results suggested a hitherto unknown role of the adaptor protein Homerla in enabling activity-dependent enhancement of calcium signal, which is likely to interfere with rules of synaptic modification. Less

  • Research Products

    (10 results)

All 2005 2004

All Journal Article (10 results)

  • [Journal Article] Essential roles of Homer-la in homeostatic regulation of pyramidal cell excitability : a possible link to clinical benefits of electroconvulsive shock2005

    • Author(s)
      Sakagami et al.
    • Journal Title

      Eur J Neurosci 21

      Pages: 3229-3239

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Homer la enhances spike-induced calcium influx via L-type calcium channels in neocortex pyramidal cells2005

    • Author(s)
      Yamamoto et al.
    • Journal Title

      Eur J Neurosci 22

      Pages: 1338-1348

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Age-dependent emergence of a parieto-insular corticocortical signal flow in developing developing rats2004

    • Author(s)
      Yoshimura et al.
    • Journal Title

      Dev Brain Res 149

      Pages: 45-51

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] To-and-fro optical voltage signal propagation between the insular gustatory an dparietal oral somatosensory areas in rat cortex slices2004

    • Author(s)
      Yoshimura et al.
    • Journal Title

      Brain Res 1015

      Pages: 114-121

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Frequency-dependent requirement for calcium store-operated mechanisms in induction of homosynatic long-term depression at hippocampus CA1 synapses2004

    • Author(s)
      Nakano et al.
    • Journal Title

      Eur J Neurosci 19

      Pages: 2881-2887

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Small conductance Ca^<2+>-dependent K^+ channels are the target of spike-induced Ca^<2+> release in a feedback regulation of pyramidal cell excitability.2004

    • Author(s)
      Yamada et al.
    • Journal Title

      J Neurophysiol 91

      Pages: 2322-2329

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Small conductance Ca^<2+>-dependent K^+ channels are the target of Spike-induced Ca^<2+> release in a feedback regulation of Pyramidal cell excitability2004

    • Author(s)
      Yamada et al.
    • Journal Title

      J Neurophysiol 91

      Pages: 2322-2329

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Frequency-dependent requirement for calcium store-operated mechanisms in induction of homosynaptic long-term depression at hippocampus CA1 synapses2004

    • Author(s)
      Nakano et al.
    • Journal Title

      Eur J Neurosci 19

      Pages: 2881-2887

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] To-and-fro optical voltage signal propagation between the insular gustatory and parietal oral somatosensory areas in rat cortex slices2004

    • Author(s)
      Yoshimura et al.
    • Journal Title

      Brain Res 1015

      Pages: 114-121

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Age-dependent emergence of a parieto-insular corticocortical signal flow in developing rats2004

    • Author(s)
      Yoshimura et al.
    • Journal Title

      Dev Brain Res 149

      Pages: 45-51

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2007-12-13  

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