[Effects of hypokinesia of different duration on electrolyte contents in muscle tissue of rats].

The study has demonstrated a significant increase in blood levels of potassium on Day 3 of hypokinesia. Sodium content and the sum of two ions were decreased on Day 3 and increased on Day 10 of the exposure. Significant changes in the calf muscles (musculus gastrocnemius), i.e. decreased potassium and increased sodium concentrations, were observed on Days 10, 30, 45, 70, 90, and 140. The total content of potassium and sodium ions remained reduced. Analysis of parameters characterising the ion gradients points to lowered activity of Na-K-dependent ATP-ase, fewer number of ion-binding groups of tissue anions. In myocardium, these shifts were less pronounced and included an insignificant loss of potassium ions and gain in sodium ions the gradient of which was most significant on Days 10, 30, and 45. The general trend of changes in the ion balance implies some unified mechanisms of the hypokinesia effects on the muscular tissue, associated with the disorders in energy metabolism, change in hormonal status, and activation of catabolic processes in immobilised body giving rise to deconditioning and asthenization.