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1999 Fiscal Year Final Research Report Summary

A New Austained inward current activeted by deporaligation in nat SAnode

Research Project

Project/Area Number 09307001
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field General physiology
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

NOMA Akimori  Kyoto-U. Dept of Physiology, Professor, 医学研究科, 教授 (00132738)

Co-Investigator(Kenkyū-buntansha) MATSUOKA Satoshi  Kyoto-U. Dept of Physiology, Professor, 医学研究科, 助手 (00263096)
SHINAGAWA Yasuko  Kyoto-U. Dept of Physiology, Professor, 医学研究科, 助手 (40093249)
MITSUIYE Tamotsu  Kyoto-U. Dept of Physiology, Professor, 医学研究科, 助教授 (40174065)
TAKANO Makoto  Kyoto-U. Dept of Physiology, Professor, 医学研究科, 助手 (30236252)
Project Period (FY) 1997 – 1999
KeywordsCardiac pacemaker / Sino-Aticalnode / Spontaneous action potential / Sustained inward current
Research Abstract

The ionic mechanisms underlying the slow diastolic depolarization in the sino-atrial node of the heart is still a matter of debate. Recently we found a new inward current, which was in fact activated by depolarization to the voltage range of the slow diastolic depolarization (-65〜-40 mV). Since the current showed little inactivation during the depolarizing pulse, we called this current IィイD2stィエD2. We aimed to clarify the nature of IィイD2stィエD2. In this research project, we found the existence of IィイD2stィエD2 in rat sinoatrial node. We developed a new method of isolating the pacemaker cells, and recorded the membrane current by applying the patch clamp method. Rat IィイD2stィエD2 was insensitive to TTX, but was blocked by the classical CaィイD12+ィエD1 antagonists, such as nicardipine, D600 and verapamil. The current is enlarged by the β adrenergic stimulation, and this effect was reversed by applying ACh.
In parallel to the whole cell study, we attempted to record the single channel current of IィイD2stィエD2. By applying the cell attached patch recording to the guinea-pig pacemaker cells, we could record a NaィイD1+ィエD1-mediated single channel current, which showed almost the same characteristics as the whole cell IィイD2stィエD2.
We are developing a new computer model of the pacemaker by including IィイD2stィエD2.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] Xie L.H.: "The inhibitory effect of propranolol on ATP-sensitive potassium channels in neonatal rat heart"British Journal of Pharmacology. 123. 599-604 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Fujioka.Y.: "Interaction of the Na^+-K^+ pump and Na^+-Ca^+ ** in a restricted ** of quinea-pig venticular alls"Journal of Physjology. 509. 457-470 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Sasaki.N: "* * during contraclion of isolated guinea-pig venticular myocyte"*. 437. 804-811 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ishii.T.M.: "Molecular characterization of the * * cation channel in rabbit heart * *node"Journal of Biological Chemistry. 274. 12835-12839 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Mitsuiye.T: "*-* Na^+ * channel * *"Journal of Physjology. 521. 69-79 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Shinagawa.Y.: "The sustained can * *"Journal of Physjology. 523. 593-605 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Xie L.H., Takano M. & Noma A.: "The inhibitory effect of propranolol on ATP-sensitive potassium channels in neonatal rat heart"British Journal of Pharmacology. 123. 599-604 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Fujioka, Y.Matsuoka S.Ban T., and Noma A: "Interaction of the NaィイD1+ィエD1-KィイD1+ィエD1 pump and NaィイD1+ィエD1-CaィイD12+ィエD1 exchange via[NaィイD1+ィエD1]ィイD2iィエD2 in a restricted space of guinea-pig ventricular cells."Journal of Physiology. 509. 457-470 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Sasaki, N., Mitsuiye T., Noma A., & Powell T.: "Sarcomere length during contraction of isolated guinea-pig ventricular myocytes."Pflugers Archiv. 437. 804-811 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Ishii T.M., Takano M., Xie L.H., Noma A., and Ohmori H.: "Molecular characterization of the hyperpolarization-activated cation channel in rabbit heart sinoatrial node."Journal of Biological Chemistry. 274. 12835-12839 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Mitsuiye T., Guo J. and Noma A: "Nicardipine-sensitive NaィイD1+ィエD1-mediated single channel currents in sinoatrial node pacemaker cells of guinea-pig."Journal of Physiology. 521. 69-79 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Shinagawa Y., Satoh H. and Noma A.: "The sustained inward current and inward rectifier KィイD1+ィエD1 current in pacemaker cells dissociated from rat sinoatrial node."Journal of Physiology. 523. 593-605 (2000)

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

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Published: 2001-10-23  

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