MITOCHONDRIA OF THE RAT LEFT-VENTRICLE UP ON HYPOKINEZIA

The response of rat cardiomyocytes and their mitochondrial system upon hypokinezia was studied. The rats were kept under conditions of hypok inezia for 4 months. Morphometric light microscopic analysis of cardio myocytes of the left ventricle has shown that the area of cell cross s ections increased, whereas the number of capillaries remained the same as in the normal heart. Hypertrophy in this case is supposed to be a weak adaptive response. In electron microscope, besides normal cardiom yocytes, cells with the swollen sarcoplasm and degrading myofibrils we re observed, which indicated a partial atrophy of the heart muscle. He terogeneous ultrastructural changes of mitochondria were also observed . Some organelles were swollen. Mitochondria with unusual dark cristae and mitochondria with cristae in ''twisted'' configuration were found . The number of intermitochondrial junctions considerably decreased in all zones of mitochondrial location. It is suggested that the latter can be related to the decrease in the functional cell activity under e xperimental hypokinezia.