PT - JOURNAL ARTICLE AU - David P. Westfall AU - Joseph J. McPhillips AU - Dennis J. Foley TI - INHIBITION OF CHOLINESTERASE ACTIVITY AFTER POSTGANGLIONIC DENERVATION OF THE RAT VAS DEFERENS: EVIDENCE FOR PREJUNCTIONAL SUPERSENSITIVITY TO ACETYLCHOLINE DP - 1974 May 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 493--498 VI - 189 IP - 2 4099 - http://jpet.aspetjournals.org/content/189/2/493.short 4100 - http://jpet.aspetjournals.org/content/189/2/493.full SO - J Pharmacol Exp Ther1974 May 01; 189 AB - The supersensitivity of the smooth muscle of the vas deferens which occurs to norepinephrine after postganglionic denervation is believed to be due to a combination of prejunctional (loss of neuronal uptake) and postjunctional changes. Evidence obtained in this study indicates that the increase in sensitivity to acetylcholine after denervation also has a prejunctional component (an inhibition of cholinestenase activity) but that the contribution of this component to the total increase in sensitivity to acetylcholine is small. Seven days after denervation, a time at which there is a 50-fold increase in sensitivity of the smooth muscle to acetylcholine, there is a marked inhibition (55%) in the hydrolysis of radiolabeled acetylcholine and methacholine by homogenates of vasa deferentia. Twenty-four hours after the administration of disulfoton (5 mg/kg), an organophosphorus cholinesterase inhibitor, there was only a 2-fold increase in the sensitivity of the smooth muscle to acetylcholine, but an inhibition of cholinesterase activity equivalent to that produced by denervation. The sensitivity of the smooth muscle to carbachol. a nonhydrolyzable ester, was increased by denervation (65-fold) but not by disulfoton. © 1974 by The Williams & Wilkins Co.