THE EFFECT OF AUTONOMIC BLOCKING AGENTS ON VASOPRESSIN RELEASE IN VIVO INDUCED BY OSMORECEPTOR STIMULATION

Abstract

SUMMARY Intracarotid injection of 0·25 ml of a hyperosmotic (1 m) sodium chloride solution into hydrated rats was an effective stimulus for vasopressin release. The effects of autonomic blocking drugs on this stimulus and on the release of vasopressin by intracarotid injections of acetylcholine were studied. Anti-adrenergic compounds (reserpine and phenoxybenzamine), ganglion-blocking agents (pempidine and pentolinium) and atropine were shown to be effective in preventing the vasopressin release caused by hyperosmotic stimulation. Acetylcholine-induced release of vasopressin was inhibited by pempidine but not reserpine. Based on these findings the nervous pathway(s) involved in the release of vasopressin induced by hyperosmolarity of the plasma is discussed.