[Mechanisms of involvement of Na+(Li+) in the process of intracellular transmission of the trigger signal in skeletal muscles].

The data obtained suggest that Li+ can replace Na+ in transmission of triggering signal from excited surface membrane of muscle fibers onto intracellular effector systems. The participation of extracellular calcium in transmission of activation into the cell being excluded, the Ca2+-activation of the contractile apparatus and kinase-phosphorylase system in electrically stimulated muscles presumably proceeds from the induction of Ca2+ release from sarcoplasmic reticulum (SR) by transmembrane Na+- or Li+-current. The chemical specific features of Na+ and Li+ displayed at that, corroborate the hypothesis of Na+-trigger mechanism of Ca2+ release from the SR in skeletal muscle fibers of vertebrates.