[Effect of the pH on the membrane resting potentials of the muscle fibers in the frog].

The pH change from 7.2 to 8.2 causes a decrease of resting membrane potential (RMP) of muscle fibers in the frog at 2.5 mM/l of potassium ions and does not affect the RMP at 5.0 mM/l in the Ringer solution. Tetrodotoxin or tetraethylammonium do not prevent the membrane depolarization after the pH change, but a lowering of temperature, ouabain or a decrease of chloride ions concentration do prevent it. Muscle denervation or blockade of axoplasmic flow by colchicine with no impairment of neuro-muscular transmission, cause a decrease of RMP of muscle fibers, and a pH change from 7.2 to 8.2 induces a hyperpolarization of the muscle membrane under these conditions. Ouabain or a lowering of temperature prevent the membrane hyperpolarization after a pH change. The data obtained suggest the possibility of chloride or proton-chloride pump existence in the frog muscle membrane and that the neurotrophic regulation of this probable mechanism is connected with axoplasmic flow.