THE EFFECT OF ACETYLCHOLINE ON THE EXCITABILITY OF THE FROG'S SARTORIUS MUSCLE

Abstract

A study of the effect of acetylcholine in Ringer''s soln. on the [alpha] strength-duration curve of the frog''s sartorius muscle shows that the drug has no effect until a conc. is reached which causes twitching of the muscle. Following the twitching, the rheobase is very low but it recovers rapidly to a value below the normal by an amt. which usually is greater, the higher the conc. of the acetylcholine. At this stage which persists for at least a few hrs. the chronaxie is considerably lengthened. On returning to Ringer''s soln. both the rheobase and chronaxie return quickly to normal. Acetylcholine apparently does not excite muscle through the same mechanism as do electrical stimuli.