RT Journal Article SR Electronic T1 EFFECT OF LOCAL ANESTHETICS ON PHARMACOLOGIC RECEPTOR SYSTEMS OF SMOOTH MUSCLE JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 44 OP 51 VO 186 IS 1 A1 FLEISCH, JEROME H. A1 TITUS, ELWOOD YR 1973 UL http://jpet.aspetjournals.org/content/186/1/44.abstract AB The effects of tetracaine and lidocaine on contractile responses of rat aorta to norepinephrine and KCl were measured and compared to the antagonism of norepinephrine and KCl by N-(2-chloroethyl)dibenzylamine hydrochloride (Dibenamine). Also, the effect of tetracaine on enrbamylcholine-induced contractions of rat trachea was investigated. Analysis of cumulative dose-response curves showed that the local anesthetics antagonized norepinephrine. carbamylcholine and KCl in a manner similar to that seen with Dibenamine. The initial parallel shift to the right of the norepinephrine and carbamycholine dose-response curves produced by the local anesthetics appeared to be caused by a change in the affinity constant of both the adrenergic and cholinergic receptors. The nonparallel shift in the dose-response curves seen with higher concentrations of the local anesthetics and the noncompetitive antagonism of the response to potassium were probably caused by the well-known effects of local anesthetics on the mobilization of Ca++ needed for smooth muscle contraction. © 1972 by The Williams & Wilkins Co.