[Quantitative ultrastructural characteristics of the myocardial mitochondria of hypokinetic rats].

Experiments on rats under 30-day hypokinesia have shown an increase in the mitochondrial area in perinuclear, myofibrillar and subsarcolemmal zones of the cardiomyocyte pericaryon, accompanied by a concurrent rise in the number of crests. The crest density index and the amount of mitochondria in te pericaryon diminish. These changes are considered as compensatory-adaptive reconstitution of hypertrophic nature in response to partial destruction of mitochondria. During the observation period this reconstitution is not completed and thus underlies the decreased contractility and functional reserves of the heart in hypokinesia.