[Polarization of nerve terminals induced by direct electrical stimulation of frog skeletal muscle]

Direct electrical stimulation (20-200/sec) of the frog skeletal muscle elicited a slow electrical response of motor nerve terminals reflecting a hyperpolarization shift of their membrane potential. A new technique for dissociation of electrical and mechanical activities of muscular fibers revealed hyperpolarization of motor terminals due to a series of APs of the muscular fibers. The terminals hyperpolarizaton response is augmented by 2-3 times with 10 mM of theophyllin. Possible mechanisms of reversed action of active muscular fibers on nerve terminals, are discussed.