Eserine and autonomic nervous control of guinea-pig vas deferens

Abstract

In the presence of eserine, the isolated preparation of guinea-pig vas deferens responds to electrical stimulation of the hypogastric nerve with enhanced contractions, which are no longer antagonised by adrenergic blocking agents but are strongly inhibited by atropine. Similarly, in preparations from reserpine-pretreated animals which have become unresponsive to the hypogastric stimulation, eserine elicits full-size responses which are almost completely abolished by atropine and not affected by adrenergic blocking drugs. Direct stimulation with acetylcholine contracts the vas deferens both of normal and reserpinised animals: the responses are antagonised by atropine and enhanced by eserine. It is concluded that there are grounds for inferring that eserine acts not by enhancing an adrenergic mechanism, but by uncovering a parasympathetic cholinergic component in the autonomic nervous control of the preparation.