Electrolyte composition of rat skeletal muscles after hypokinesia

It has been suggested that the electrolyte composition of rat skeletal muscles may change after the exposure to hypokinesia (diminished muscular activity). Thus, the aim of this study was to determine the concentration levels of ions of Na, K, Ca and Mg in muscle tissue and the endogenous media of 135 rats weighing 140-160 g during the readaptation period (RP) of 30 days and after a 96 days exposure to hypokinesia (HK). The animals were divided into two groups. The 1st group (70 rats) was subjected to "pure" HK, that is, without the use of any preventive measures, and the 2nd group (65 rats) was placed under usual conditions and served as control. For the simulation of the hypokinetic effect, the 1st group of rats were kept in small individual cages made of plexiglass. The concentration levels of ions of Na, K, Ca and Mg were determined in muscle tissue and the endogenous media of rats by the method of atom-absorption spectrophotometry. Blood plasma ion composition changed significantly. Tissular fluid content and the tissular concentrations of Na, K, Ca and Mg in muscles also changed significantly during the readaptation period. It was concluded that the concentration levels of ions of Na, K, Ca and Mg in connective tissues, as well as endogenous medium of rats evidently changed significantly during the readaptation period and after the exposure to hypokinesia.