THE PHARMACOLOGICAL REACTIVITY OF PRESYNAPTIC NERVE TERMINALS IN A SYMPATHETIC GANGLION

¹ Laboratory of Pharmacology, School of Medicine, University of Pennsylvania Philadelphia, Pennsylvania

This report describes the effects of several quaterimary ammonium compounds on the superior cervical ganglionic synapse of the lightly anesthetized cat. Close intraarterial injections of acetyleholine evoke electrical potentials in the pre- and postsynaptic nerves of this ganglion. The drug-inoluced presynaptic potentials are antidromically conolucted, and originate at the presynaptic nerve-termrimnals. A ganglion-blocking drug, hexamethmonium, has also been studied and found to have a presynaptic locus of action. The findings are discussed with special reference to time significance of the presynaptic nerve terminal as a site of drug action.