[Decrease of mitochondrial sensitivity to Ca2+-induced pore opening during long-term incubation].
It is shown that mitochondria of rat myocardium exhibit high sensitivity to Ca2+-induced permeability transition pore (PTP) during an hour after their isolation. The threshold Ca2+ concentrations necessary to induce PTP are as low as 25-50 nmol/mg of protein. Apparent K(Ca) constant of Ca2+-dependent PTP activation is 40 microM. Incubation of mitochondria during 2, 3 and 4 hours after their isolation leads to gradual increase in K(Ca) values up to 0.4 microM, which is accompanied by simultaneous decrease in sensitivity of mitochondria to pore opening. A correlation is supposed between changes of kinetic parameters of Ca2+-uniporter and changes in sensitivity of mitochondria to Ca2+-induced permeability transition.
Akopova
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Sagach
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D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology*; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D015640:Ion Channel Gating / Q000187:drug effects*; D007473:Ion Channels / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D051381:Rats; D013997:Time Factors
D007473:Ion Channels; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D002122:Calcium Chloride