Effect of pH on Twitch Facilitating Potency of 3-Hydroxyphenyltriethyl-ammonium Ion. ∗

Summary

Ability of 3-hydroxyphenyl-triethylammonium ion to facilitate the response of rat phrenic nerve diaphragm to single supramaximal stimuli has been tested for pH dependence. It is concluded that the phenolate ion is more active in this regard than is the unionized phenol, and that, therefore, the receptor sites for this action on the motor nerve terminals differ from those ascribed to the cholinesterase enzyme.