[Molecular organization of the sarcoplasm of skeletal muscles in different functional states].

Changes in the molecular substrate of the frog gastrocnemius muscle sarcoplasm were studied at rest, under indirect suprathreshold stimulation and fatigue. The time course of changes in the sarcoplasm was evaluated from the intensity of recordable mitogenetic radiation of the muscle. At rest the muscle sarcoplasm was characterized by active maintenance of the functional integrity of nerve and muscle fibers, whereas under indirect stimulation and during fatigue this coordinating function was disturbed. Thus, the sarcoplasm is an important link in the regulation of coordinated changes in different structural elements of the muscle.