[Morhologic study of the hearts of rats exposed aboard biosatellites].

The hearts of rats exposed for 22.5 and 19.5 days aboard the biosatellites Cosmos-605 and Cosmos-782 were examined histologically and histochemically. Prolonged space flight induced no essential structural or metabolic changes in the myocardium of rats. The absolute weight of the heart remained unchanged. A short-term increase in the phosphorylase activity of the myocardium recorded 10 to 11 hours after the flight can be attributed to the complex of stress effects accompanying the recovery of the biosatellites.