Calcium reversal: inhibition by Ca ion of sustained contraction in Ca-free medium induced by various agonists in rat uterine smooth muscle.
Various agonists induced sustained contractions of estrogen-dominated rat uterine smooth muscle in Ca-free salt solution containing 0.2 mM EGTA after incubation of the muscle with 3 mM EGTA for 1 hr. The magnitudes of contraction varied with agonists. (bradykinin greater than oxytocin greater than or equal to vasopressin greater than PGF2 alpha greater than angiotensin II greater than acetylcholine greater than or equal to PGE2 greater than or equal to 5-hydroxytryptamine. Addition of 10(-4) Ca ion reduced the tension developed: Ca ion inhibited these contractions when they were sufficiently large (marked inhibition on bradykinin-, oxytocin-, and vasopressin-induced contractions; definite one on PGF2 alpha-induced contraction), as observed previously with oxytocin-induced contraction under the same conditions and named "Ca Reversal".
D000109:Acetylcholine / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002369:Castration; D015237:Dinoprost; D015232:Dinoprostone; D004533:Egtazic Acid / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000187:drug effects*; D009215:Myometrium / Q000187:drug effects; D011458:Prostaglandins E / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology; D014590:Uterine Contraction / Q000187:drug effects*; D014667:Vasopressins / Q000494:pharmacology
D011458:Prostaglandins E; D011460:Prostaglandins F; D014667:Vasopressins; D000804:Angiotensin II; D012701:Serotonin; D004533:Egtazic Acid; D015237:Dinoprost; D015232:Dinoprostone; D000109:Acetylcholine; D001920:Bradykinin; D002118:Calcium