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1998 Fiscal Year Final Research Report Summary

Membrane dysfunction induced by in vitro ischemia in rat hippocampal CA1 pyramidal neurons

Research Project

Project/Area Number 09470337
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Anesthesiology/Resuscitation studies
Research InstitutionKurume University

Principal Investigator

HIGASHI Hideho  Kurume Univ.Sch.Med.Professor, 医学部, 教授 (10098907)

Co-Investigator(Kenkyū-buntansha) YAMAMOTO Satoshi  Kurume Univ.Sch.Med.Assistant, 医学部, 助手 (60220464)
INOKUCHI Hiroe  Kurume Univ.Sch.Med.Associate Professor, 医学部, 助教授 (10080558)
Project Period (FY) 1997 – 1998
KeywordsBrain ischemia / Hippocampal CA 1 neurons / Necrosis / Rapid depolarization / Small blebs / Cell swelling / Ca^<2+> antagonists / Synaptic responses
Research Abstract

Intracellular and single-electrode voltage-clamp recordings were made to investigate the process of membrane dysfunction induced by superfusion with oxygen and glucose-deprived (isehemia-simulating) medium in hippocampal CAl pyramidal neurons of rat tissue slices. To assess correlation between potential change and membrane dysfunction, the recorded neurons were intracellularly stained with biocytin. A rapid depolarization was produced approximately 6 min after starting superfusion with ischemia-simulating medium. When oxygen and glucose were reintroduced immediately after generating the rapid depolarization, the membrane did not repolarize ; the potential reached 0 mV approximately 5 min after the reintroduction. In single-electrode voltage-clamp recording, supeffusion with ischemia-simulating medium for 4 min depressed the glutamate-mediated fast EPSCs, and abolished the GABA-mediated fast and slow IPSCs. Contrary, both exogenous glutamate- and GABA-induced inward current were augment … More ed, but muscimol-and baclofen-induced outward currents were suppressed. These results suggest that the site of the depression of the fast EPSC or the fast IPSC is presynaptic while the site of the suppression of the slow IPSC is pre-and post-synaptic. The morphological aspects of biocytin-stained neurons during ischemic exposure were not significantly different from control neurons before the rapid depolarization. On the other hand, small blebs were observed on the surface of the neuron within 0.5 min of generating the rapid depolarization and blebs increased in size after i min. After 3 min, neurons became larger and swollen. When Ca^<2+>-free (0 mM) with Co^<2+> (2.5 mM)-containing medium including oxygen and glucose was applied within 1 min after the rapid depolarization, the membrane potential was completely restored to the preexposure level. In these neurons, the long axis was lengthened without any blebs being apparent on the membrane surface. These results suggest that the membrane dysfunction induced by in vitro ischemia may be due to a Ca^<2+>-dependent process which commences around 1.5 min after, and is completed 3 min after the onset of the rapid depolarization. From all the results, it is concluded that the transformation from small to large blebs may result in the observed irreversible membrane dysfunction. Less

  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] Fujimura N et al: "Contribution of ATP-senstive potassium channels to hypoxic hyperpolarization in rat hippocampal CAl neurons in vitro" Journal of Neurophysiology. 77. 378-385 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yamamoto S et al: "Mediation by intracellular calcium-dependent signals of hypoxic hyperpolarization in rat hippocampal CA1 neurons in vitro" Journal of Neurophysiology. 77. 386-392 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tamala E et al: "Mechanism underlying the rapid depolarization produced by deprivation of oxygen and glucose in rat hippocampal CA1 neurons in vitro" Journal of Neurophysiology. 78. 891-902 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yamamoto S et al: "Factors that reverse the persistent depolarization produced by deprivation of oxygen and glucose in rat hippocampal CA1 neurons in vitro oxygen and glucose in rat hippocampal CA1 neurons in vitro" Journal of Neurophysiology. 78. 903-911 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Onitsuka M et al: "Mild hypotermia protects rat hippocampal CA1 neurons from irreversible membrane dysfunction induced by experimental ischemia" Neuroscience Research. 30. 1-6 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Onitsuka M et al: "Nitric oxide contributes to irreversible membrane dysfunction caused by experimental ischemia in rat hippocampal CA1 neurons" Neuroscience Research. 30. 7-12 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Isagai T et al: "Journal of Neurophysiology" Membrane dysfunction induced by in vitro ischemia in immature rat hippocampal CA1 neurons., (in press)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tanaka E et al: "Journal of Neurophysiology" Membrane dysfunction induced by in vitro ischemia in rat hippocampal CA1 pyramidaeql neurons., (in press)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Fujimura N,Tanaka E,Yamamoto S,Shigemori M,Higashi H: "Contribution of ATP-sensitive potassium channels to hypoxic hyper-polarization in rat hippocampal CA1 neurons in vitro." J.Neurophysiol.77. 378-385 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yamamoto S,Tanaka E,Higashi H: "Mediation by intracellular calciumdependent signals of hypoxic hyperpolarization in rat hippocampal CA1 neurons in vitro." J.Neurophysiol.77. 386-392 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tanaka E,Yamamoto S,Kudo Y,Mihara S,Higashi H: "Mechanisms underlying the rapid depolarization produced by deprivation of oxygen and glucose in rat hippocampal CA1 neurons in vitro." J.Neurophysiol.78. 891-902 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yamamoto S,Tanaka E,Shoji Y,Kudo Y,Inokuchi H,Higashi H: "Factors that reverse the persistent depolarization produced by deprivation of oxygen and glucose in rat hippocampal CA1 neurons in vitro." J.Neurophysiol.78. 903-911 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Onitsuka M,Mihara S,Inokuchi H,Shigemori M,Higashi H: "Mild hypo-termia protects rat hippocampal CA1 neurons from irreversible membrane ischemia." Neurosci. Res.30. 1-6 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Onitsuka M,Mihara S,Yamamoto S,Shigemori M,Higashi H: "Nitric oxide contributes to irreversible membrane dysfunction caused by experimental ischemia in rat hippocampal CA1 neurons." Neurosci. Res.30. 7-12 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Shoji Y,Tanaka E,Yamamoto S,Maeda H,Higashi H: "Mechanisms under-lying the enhancement of excitatory synaptic transmission in basolateral amygdala neurons of the kindlingrat." J.Neurophysiol.80. 638-646 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Isagai T,Fujimura N,Tanaka E,Yamamoto S,Higashi H: "Membrane dysfunction induced by in vitro ischemia in immature rat hippocampal CA1 neurons." J.Neurophysiol.(in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tanaka E,Yamamoto S,Inokuchi H,Isagai T, Higashi H: "Membrane dysfunction induced by in vitro ischemia in rat hippocampal CA1 pyramidal neurons." J.Neurophysiol.(in press).

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

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Published: 1999-12-08  

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