Flow cytometric analysis of Ca2+-induced membrane permeability transition of isolated rat liver mitochondria

Teruo Umegaki, Yuya Okimura, Hirofumi Fujita, Hiromi Yano, Jitsuo Akiyama, Masayasu Inoue, Kozo Utsumi, Junzo Sasaki

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


The membrane permeability transition (MPT) of mitochondria plays an important role in the mechanism of apoptotic cell death in various cells. Classic type MPT is induced by Ca2+ in the presence of inorganic phosphate and respiratory substrate, and is characterized by various events including generation of reactive oxygen species (ROS), membrane depolarization, swelling, release of Ca2+ and high sensitivity to cyclosporine A. However, the sequence of these events and the effect of antioxidants on their events remain obscure. Flow cytometry is a convenient method to investigate the order of events among various functions occurring in MPT using a limited amount of mitochondria (200 μl of 0.02 mg protein/ml) without contamination by other organelles. Flow cytometric analysis revealed that Ca2+ sequentially induced ROS generation, depolarization, swelling and Ca2+ release in mitochondria by a cyclosporine A-inhibitable mechanism. These results were supported by the finding that Ca2+-induced MPT was inhibited by antioxidants, such as glutathione and N-acetylcysteine. It was also revealed that various inhibitors of Ca2+-induced phospholipase A2 suppressed all of the events associated with Ca2+-induced MPT. These results suggested that ROS generation and phospholipase A2 activation by Ca2+ underlie the mechanism of the initiation of MPT.

Original languageEnglish
Pages (from-to)35-44
Number of pages10
Journaljournal of clinical biochemistry and nutrition
Issue number1
Publication statusPublished - Jan 2008
Externally publishedYes


  • Antioxidant
  • Flow cytometric analysis
  • Membrane permeability transition
  • Mitochondria
  • Phospholipase A

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Clinical Biochemistry


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