Functional state of myocardial mitochondria in ischemia reperfusion of the heart in rats adapted to hypoxia.

Parameters of respiration, transmembrane potential, and Ca(2+)-binding capacity of mitochondria isolated from Langendorff-perfused hearts of rats adapted to normobaric hypoxia were analyzed. Ischemia and reperfusion modeling in intact and adapted animals reduced Ca(2+)-binding capacity of mitochondria, which indicated increased sensitivity of mitochondrial permeability transition pores (MPTP) to calcium ions. These changes were accompanied by a decrease in transmembrane potential, ADP/O coefficient (ratio of added ADP to oxygen consumption in State 3), and inhibition of State 3 respiration. At the same time, adaptation attenuated the negative effect of ischemia and reperfusion on the functional state of mitochondria.