The Effect of Variations in the Intra- and Extracellular Ion Concentrations upon the Electrical Activity of Normal and Dystrophic Mouse Skeletal Muscle

The resting and action potentials of the m. gastrocnemii of normal and dystrophic mice have been measured in vitro, under various conditions of the ionic environment. The observed effects are consistent with the view that, when equilibrium is established between internal and external ionic concentrations, the resting potential is determined very largely, and perhaps entirely, by the gradient of K ions. Action potentials are associated with a greatly increased Na conductance in this as in other excitable tissues. No differences in electrical activity between normal and dystrophic muscle cells could be established.