EFFECT OF 2-METHYL NAPHTHOQUINONE ON THE ACTION POTENTIAL OF NERVE AND MUSCLE

Abstract

-The effect of 2-methyl naphtho- quinone , a potent and probably specific inhibitor of choline acetyl-ase, on the function of nerve and muscle was investigated on isolated frog nerve, isolated frog nerve-muscle prepns., and nerve-muscle prepns. of mouse and rat in situ. In the presence of low concns. of the naphthoquinone the latency and the threshold increased and the amplitude of the action potential of nerve and muscle decreased. The muscle function on direct stimulation was not significantly impaired. Since the naphthoquinone, in the concns. used, is known to inhibit only the activity of choline acetylase, the dysfunction observed suggests that acetylcholine is necessary to maintain an optimal function of nerve.