INHIBITION AND IMPULSE SUMMATION AT THE MAMMALIAN NEUROMUSCULAR JUNCTION

Abstract

In curarized dogs a single motor nerve volley leaves a brief junctional facilitation, followed by inhibition lasting 10 secs, or longer. If Mg is substituted for curare facilitation follows the same time course, but inhibition is relatively feeble and brief. Eserine does not prolong facilitation in either case, and its failure to do so is not due to rapid loss of its anticholinesterase activity. Low-frequency stimulation of the nerve, under curare or after excess acetylcholine. prevents effective latent addition of 2 interposed volleys; under Mg there is no such interference.