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2002 Fiscal Year Final Research Report Summary

Analysis of synaptic mechanisms in cochlear hair cells by measuring membrane capacitance

Research Project

Project/Area Number 13671789
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Otorhinolaryngology
Research Institution宮崎医科大学

Principal Investigator

KIMITSUKI Takashi  Miyazaki Medical College, Otorhinolaryngology, Lecturer, 医学部, 講師 (50240908)

Co-Investigator(Kenkyū-buntansha) TSUBOI Yasuhiro  Miyazaki Medical College, Otorhinolaryngology, Assistant Professor, 医学部, 助手 (70284841)
Project Period (FY) 2001 – 2002
Keywordscochlea / inner hair cell / membrane capacitance / endocytosis / exocytosis / ion channel / potassium current / frequency analysis
Research Abstract

We measured the membrane current possessing the properties of mechano-electric transducer current in isolated inner hair cells of guinea-pig cochlea. In free-standing hair bundle, depolarization to +80 mV evoked a stable outward current attributable to the opening of transducer channels and repolarization to -80 mV evoked a transient inward current indicating adaptation followed. Time constant of adaptation increased as the membrane potential depolarized. Dihydrostreptomycin diminished both the outward and inward currents.
Cyclopiazonic acid (CPA) is a reticulum-like intracellular Ca^<2+> store depletory, which raises intracellular Ca^<2+> concentration. The effect of CPA on membrane currents in isolated inner hair cells (IHCs) from guinea-pig cochlea was investigated by the patch-clamp technique in the whole-cell configuration. Four out of eight IHCs showed an augmentation of the currents and the other four cells showed an inhibition of the currents by extracellular CPA application. The activation kinetics of outward currents were not changed by CPA. Three out of four IHCs obtained from the basal part of the cochlea demonstrated augmentation, whereas three out of four IHCs from the apical part demonstrated inhibition of the currents. This result suggests that Ca^<2+>-activated currents were dominant in the basal IHCs of the cochlea.

  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] Takashi Kimitsuki et al.: "Membrane current possessing the properties of a mechano-electric transducer current in inner hair cells of guinea-pig cochlea"Brain Research. 915.1. 101-103 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takashi Kimitsuki et al.: "Effect of cyclopiazonic acid on membrane currents in isolated inner hair cells from guinea-pig cochlea"Neuroscience Letters. 323. 211-214 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Takashi Kimitsuki et al.: "Effect of cyclopiazonic acid on membrane currents in isolated inner hair cells from guinea-pig cochlea"Neuroscience Letters. 323. 211-214 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takashi Kimitsuki et al.: "Membrane current possessing the properties of a mechano-electric transducer current in inner hair cells of guinea-pig cochlea."Brain Research. 915.1. 101-103 (2001)

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

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Published: 2004-04-14  

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