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Therapeutic measures of brain ischemia from the point of view of mitochondrial potential.

Research Project

Project/Area Number 16390452
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Anesthesiology/Resuscitation studies
Research InstitutionOKAYAMA UNIVERSITY

Principal Investigator

MORITA Kiyoshi  Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Professor, 大学院医歯薬学総合研究科, 教授 (40108171)

Co-Investigator(Kenkyū-buntansha) TAKEDA Yoshimasa  Okayama University Hospital, Research Associate, 医学部・歯学部附属病院, 助手 (30294466)
Project Period (FY) 2004 – 2006
Project Status Completed (Fiscal Year 2006)
Budget Amount *help
¥12,100,000 (Direct Cost: ¥12,100,000)
Fiscal Year 2006: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥5,200,000 (Direct Cost: ¥5,200,000)
Fiscal Year 2004: ¥3,500,000 (Direct Cost: ¥3,500,000)
KeywordsMitochondria / Brain ischemia / Respiratory chain / エネルギー動態
Research Abstract

In the present experiment, we developed a new system which enables to observe mitochondrial potential in vivo. Mitochondrial potential was measured using a potentiometric dye, JC-1, which accumulates in a potential-dependent manner in mitochondria and subsequently forms J-aggregates from monomers. Since J-aggregates and monomers fluoresce red (590 nm) and green (530 nm), respectively, with excitation light (485 nm), the ratio of red / green indicates mitochondrial potential. Dye loading was performed by injecting 2 μl of dye (JC-1, 6 μM ; cyclodextrine, 20% ; DMSO, 0.5% ; in physiological saline) into the parieto-temporal cortex through the DC electrode over a period of 2 minutes. During the dye loading, DC potential was stable and no spreading depression was observed. In a pilot study, it was confirmed that no histological change (hematoxylin-eosin staining) was induced during a period of 24 hours after the injection of JC-1 dye. The excitation light (2 seconds exposure in each emission) was produced by a 150-watt xenon lamp and was conducted to the cortical surface through a optical fiber (diameter, 5 mm). An iris was placed between the xenon lamp and the optical fiber to prevent photooxidation of the dye. The intensities of red fluorescence and green fluorescence in an area (470 X 470 μm) adjacent to the DC-recording site were measured every 20 seconds using an electrically cooled CCD camera mounted on a macro scope with green and red bandpass filters. The ratio of red / green fluorescence, indicative of mitochondrial potential, was normalized to that of the control value of the red / green ratio. We found that mitochondria consume ATP during ischemia by reversing ATP synthetase activity, which compromises cellular membrane potential by consuming ATP and that the mitochondrial potential is decreased with use of Diazoxide, which induces chemical preconditioning.

Report

(4 results)
  • 2006 Annual Research Report   Final Research Report Summary
  • 2005 Annual Research Report
  • 2004 Annual Research Report
  • Research Products

    (2 results)

All 2004

All Journal Article (2 results)

  • [Journal Article] Mitochondria consume energy and compromise cellular membrane potential by reversing ATP synthetase activity2004

    • Author(s)
      Yoshimasa Takeda
    • Journal Title

      Journal of Cerebral Blood Flow and Metabolism 24・9

      Pages: 986-992

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2006 Final Research Report Summary 2004 Annual Research Report
  • [Journal Article] Sick Mitochondria consume energy and compromise cellular membrane potential by reversing ATP synthetase activity during focal ischemia in rats.2004

    • Author(s)
      Yoshimasa Takeda, Miguel A.Perez-Pinzon, Myron D.Ginsberg, Thomas J.
    • Journal Title

      J Cereb Blood Flow Metab 24

      Pages: 986-992

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2006 Final Research Report Summary

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Published: 2004-04-01   Modified: 2016-04-21  

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