TY - JOUR T1 - ZINC AND SMOOTH MUSCLE CONTRACTILITY I. STUDY OF THE MECHANISMS OF ZINC-INDUCED CONTRACTILITY CHANGES IN RAT UTERI JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 282 LP - 289 VL - 178 IS - 2 AU - E. E. DANIEL AU - SYLVIA FAIR AU - A. M. KIDWAI AU - I. POLACEK Y1 - 1971/08/01 UR - http://jpet.aspetjournals.org/content/178/2/282.abstract N2 - Zinc ion in concentrations of 10-6 through 10-4 M potentiated contractile responses of rat uteri to submaximal doses of acetylcholine; 10-8; M zinc ion inhibited maximal and submaximal responses. Zinc's potentiation of contractile responses was not related to energy supply (adenosine triphosphate and adenosine diphosphate levels unchanged), to levels of 3', 5'-cyclic adenosine monophosphate (unchanged), to levels of Ca, Na or K in the tissues, to improved conduction of electrical activity or to zinc levels in the tissue. Altered excitation-contraction coupling involving prolonged binding of zinc at superficial sites was the postulated explanation. Inhibition of contractile activity by zinc ion was not related to changes of any of the following substances in the tissue: adenosine triphosphate, adenosine diphosphate, cyclic-adenosine monophosphate, Na, K or Ca. It may have been related to inhibited conduction of action potentials and contractility after zinc uptake and prolonged binding in myometrial cells. © 1971 by The Williams & Wilkins Co. ER -