Intracellular activity of sodium in normal and dystrophic skeletal muscle from C57BL/6J mice.
Potassium and sodium ion-selective microelectrodes were used in vitro to investigate the depolarization of skeletal muscle fibers associated with muscular dystrophy. In dystrophy there was a large increase of intracellular Na activity and an associated decrease in K activity in fibers of extensor digitorum longus muscles. Despite this, the recorded membrane potential was very close to the calculated potassium equilibrium potential (Ek) in dystrophic fibers. In contrast, in normal muscle fibers, Em was significantly depolarized with respect to Ek. The data suggest that in dystrophic fibers there is an increase in the relative membrane permeability to potassium over sodium.
D000818:Animals; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000187:drug effects*; D009132:Muscles / Q000187:drug effects / Q000502:physiology* / Q000503:physiopathology; D009137:Muscular Dystrophy, Animal / Q000503:physiopathology*; D011188:Potassium / Q000494:pharmacology*; D012964:Sodium / Q000494:pharmacology*
D012964:Sodium; D011188:Potassium