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Updated: Aug 10, 2026

Multi-parameter Measurement of the Permeability Transition Pore Opening in Isolated Mouse Heart Mitochondria
Published on: September 7, 2012
The permeability transition pore as a mitochondrial calcium release channel: a critical appraisal
1CNR Unit for the Study of Biomembranes, Department of Biomedical Sciences, University of Padova, Italy.
Abstract:
Mitochondria from a variety of sources possess an inner membrane channel, the permeability transition pore. The pore is a voltage-dependent channel, activated by matrix Ca2+ and inhibited by matrix H+, which can be blocked by cyclosporin A, presumably after binding to mitochondrial cyclophilin. The physiological function of the permeability transition pore remains unknown. Here we evaluate its potential role as a fast Ca2+ release channel involved in mitochondrial and cellular Ca2+ homeostasis. We (i) discuss the theoretical and experimental reasons why mitochondria need a fast, inducible Ca2+ release channel; (ii) analyze the striking analogies between the mitochondrial permeability transition pore and the sarcoplasmic reticulum ryanodine receptor-Ca2+ release channel; (iii) argue that the permeability transition pore can act as a selective release channel for Ca2+ despite its apparent lack of selectivity for the transported species in vitro; and (iv) discuss the importance of mitochondria in cellular Ca2+ homeostasis, and how disruption of this function could impinge upon cell viability, particularly under conditions of oxidative stress.
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