Decrease of mitochondrial sensitivity to Cа2+-induced pore opening during long-term incubation
It is shown that mitochondria of rat myocardium exhibit high sensitivity to Са2+-induced permeability transition pore (PTP) during an hour after their isolation. The threshold Са2+ concentrations necessary to induce PTP are as low as 25–50 nmol/mg of protein. Apparent KCa constant of Са2+-dependent PTP activation is 40 mM. Incubation of mitochondria during 2, 3 and 4 hours after their isolation leads to gradual increase in KCa values up to 0.4 mM, which is accompanied by simultaneous decrease in sensitivity of mitochondria to pore opening. A correlation is supposed between changes of kinetic parameters of Са2+-uniporter and changes in sensitivity of mitochondria to Са2+-induced permeability transition.
Published at the site: 2004-10-10
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