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Study on <Na^+> - <K^+> pump activity of glial cells in cortex from a warm-blooded animal.

Research Project

Project/Area Number 59570068
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Neurophysiology and muscle physiology
Research InstitutionGifu University (1986)
Kanagawa Dental College (1984-1985)

Principal Investigator

ONOZUKA Minoru  Gifu University School of Medicine, 医学部, その他 (90084780)

Project Period (FY) 1984 – 1986
Project Status Completed (Fiscal Year 1986)
Budget Amount *help
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1985: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1984: ¥1,100,000 (Direct Cost: ¥1,100,000)
KeywordsGlial cell / <Na^+> - <K^+> pump / potassium / sodium / ATPase activity / cerebral cortex
Research Abstract

The characteristics of a glial <Na^+> - <K^+> pump dependent on extracellular <K^+> within epileptogenic cortex were studied electrophysiologically, biochemically and histochemically in vitro using slices from either cobalt- or kainic acid-induced epileptogenic cortex of rat. When the extracellular <K^+> concentration ([ <K^+> ]) was varied between 4 and 40 mM, the mean slope of membrane potential plotted against <[K^+]+o> was about 57 mV in glia from the normal cortex (tissue A) and about 44 mV in glia from the epileptogenic cortex (tissue B); whereas no significant difference in the resting membrane potential of these tissues was observed. In glia from tissue B, a marked transient hyperpolarizarion above control level was caused by replacement of elevated <[K^+]_o> with the normal medium. Ouabain abolished these phenomena observed in glia from tissue B, but had no effect on the membrane potential during normal <[K^+]_o> . Reduction of extracellular <Na^+> , <Ca^(2+)> and <Cl^-> did not significantly affect the membrane potential of glia from either tissue, In tissue A, the cells marked by intracellular injection of horseradish peroxidase after intracellular recording were protoplasmic astrocytes; in tissue B, fibrous astrocyte with abnormal processes predominated. <K^+> -dependent stimulation of ( <Na^+> , <K^+> )-ATP-ase activity of the astrocyte-enriched fraction and its membrane preparation from tissue B was much larger than that from tissue A. A certain amount of the reaction product of <K^+> -pNPPase activity was seen on glial plasma membrane within tissue B but not on that from tissue A. These results suggest that epileptogenic cortex may be modified to increase in its activity.

Report

(1 results)
  • 1986 Final Research Report Summary
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Minoru Onozuka: Experimental Neurology. 94. 802-807 (1986)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Minoru Onozuka: Biochemical Pharmacology,in press.(1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Minoru Onozuka: Brain Research,in press.(1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Shizuko Imai: Experientia. (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Minoru Onozuka: "Stimulation of synapsin 1 phosphorylation in synaptosomes by convulsants." Experimental Neurology. 94. 802-807 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Minoru Onozuka: "Involvement of pentylenetetrazole in synapsin 1 phosphorylation associated with calcium influx in synaptosomes from rat cortex." Biochemical Pharmacology, in press.(1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Shizuko Imai: "Use of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and N-(6-aminohexyl)-1-naphthalenesulfonamide to determine <Ca^(2+)> /calmodulin-dependent events linking <Ca^(2+)> influx in rat cortical synaptosomes." Experientia, in press.(1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary
  • [Publications] Minoru Onozuka: "Modification of the <Na^+> - <K^+> pump of glial cells within cobalt-induced epileptogenic cortex of rat." Brain Research, in press.(1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1986 Final Research Report Summary

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Published: 1987-03-31   Modified: 2016-04-21  

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