RT Journal Article SR Electronic T1 STUDIES ON THE MECHANISM OF ANTIHYPERTENSIVE ACTION OF DIAZOXIDE: IN VITRO VASCULAR PHARMACODYNAMICS JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 531 OP 539 VO 158 IS 3 A1 Arnold J. Wohl A1 Lorraine M. Hausler A1 Franklin E. Roth YR 1967 UL http://jpet.aspetjournals.org/content/158/3/531.abstract AB Diazoxide (7-chloro-3-methyl-2H-1 ,2,4-benzothiacliazine-1 , 1-dioxide), a nondiuretic benzothiadiazine antihypertensive agent, attenuates vascular responses to a variety of vasoconstrictor substances. An in vitro pharmacodynamic study was designed to specify the type or types of inhibition involved in this vascular action. The results indicate that diazoxide competes with barium for a specific receptor site in the vascular smooth muscle of the rat aorta. The location of this receptor is apparently closer to the process of muscle contraction than the alpha-adrenergic receptor, and may be a site normally activated by calcium. The specific competitive inhibition of barium-stimulated vasoconstriction by diazoxide may help to explain the mechanism by which diazoxide, and possibly other benzothiadiazine antihypertensive agents (e.g., chlorothiazide), reduces blood pressure. © 1967 by The Williams & Wilkins Company