THE EFFECTS OF PHENOTHIAZINE DERIVATIVES ON THE NEUROMUSCULAR JUNCTION

Abstract

The neuromuscular blocking properties of several phenothiazine derivatives, such as Chlorpromazine, Levomepromazine, Promethazine and Prochlorperazine were studied using rat phrenic-diaphragm preparation (Bülbring's method) and tood sciatic-sartorius preparation (Ozawa's method) and following results were obtained :
These four compounds have been found to possess a neuromuscular blocking action. Small dose of them caused increase of responses to both direct and indirect stimulation in the early stage, then gradually caused depression on the responses to indirect stimulation while no effect on the responses to direct stimulation. Large doses of them caused paralysis of muscle and both responses decreased simultaneously. Chlorpromazine was most effective among four compounds tested. No antagonistic effects were observed between these blocking agents and Eserine or K⁺.