title: Mobilization of intracellular calcium as a mechanism for the positive inotropic effect by prostaglandin F2 alpha in isolated guinea pig atria.
abstract: The mechanism of the positive inotropic effect of prostaglandin F2 alpha (PGF2 alpha) was investigated using spontaneously beating isolated guinea pig atria. PGF2 alpha increased the contractile force in a concentration dependent fashion in a range between 10(-7)M to 10(-5)M. The maximal response to PGF2 alpha was obtained within 5 min and continued for at least 20 min. This positive inotropic effect of PGF2 alpha was not affected by verapamil, but was inhibited by procaine or TMB-8, potent inhibitors of Ca2+ release from intracellular Ca2+ compartments. Increase in extracellular Ca2+ concentration failed to provoke a significant positive inotropic effect by PGF2 alpha, suggesting that this response is relatively independent of extracellular Ca2+. These results suggest that the PGF2 alpha-mediated positive inotropic effect is produced by a mobilization of intracellular Ca2+.
authors.forename: H
authors.initials: H
authors.lastname: Otani
authors.forename: J
authors.initials: J
authors.lastname: Sugimoto
authors.forename: M
authors.initials: M
authors.lastname: Morita
mesh_terms: D000818:Animals; D016275:Atrial Function; D002118:Calcium / Q000502:physiology*; D002451:Cell Compartmentation; D015237:Dinoprost; D004305:Dose-Response Relationship, Drug; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D011343:Procaine / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D011460:Prostaglandins F; D011343:Procaine; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D015237:Dinoprost; D014700:Verapamil; D002118:Calcium