[Evaluation of structuro-functional heterogeneity of isolated mitochondria from the normal and the ischemic myocardium].

The structural and functional heterogeneity of mitochondria isolated from intact and ischemic (after 60 min exposure at 37 degrees C) rabbit myocardium was evaluated. In the presence of cytochrome c. a relatively high (260 +/- 26 ng at O/min .

[Reasons for disorders of fatty acid oxidation in isolated heart mitochondria during ischemia].

The influence of malate and cytochrome c on fatty acid oxidation under control and ischemic conditions was investigated. In the medium without malate, cytochrome did not make fatty acid oxidation decreased during ischemia return to normal. Oxidation in the media containing malate and cytochrome did not differ from control only when it was measured after preliminary oxidation of endogenous substrates.

[Estimation of intact outer and inner membranes of heart mitochondria].

A simple procedure is developed for estimation of the damage rate of inner membrane of heart mitochondria. In the assay the rate of succinate oxidation was measured using bromthymol blue as an inhibitor of succinate transport. Bromthymol blue at low concentration (12 microM) functioned as a mixed type inhibitor of succinate oxidation, whereas at high concentrations--as uncompetitive inhibitor.

[Effect of ischemia on the functional activity and membrane permeability of heart mitochondria].

Effect of ischemia and cytochrome c on oxidation of pyruvate and malate as well as of 3-hydroxybutyrate, succinate and exogenous NADH was studied. Respiration of mitochondria at the state 3 was markedly decreased in presence of the mixtures free of cytochrome c and containing pyruvate and malate, 3-hydroxybutyrate and succinate. In the same mixtures, but containing cytochrome c, oxidation of NAD-dependent substrates was decreased less distinctly and oxidation of succinate was similar to the control values.

[Changes in the quantitative composition of cytochromes and the functional activity of heart mitochondria during ischemia].

Differential cytochrome spectra and their fourth degree derivatives were recorded at 77 degrees K temperature. During myocardial ischemia (2-h autolysis), only cytochrome c content was found to be decreased in isolated mitochondria. According to these data mitochondrial state 3 respiration with succinate decreased only in a medium without cytochrome c.