Mobilization of intracellular calcium as a mechanism for the positive inotropic effect by prostaglandin F2 alpha in isolated guinea pig atria.
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+.
Otani
H
H
Sugimoto
J
J
Morita
M
M
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
D011460:Prostaglandins F; D011343:Procaine; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D015237:Dinoprost; D014700:Verapamil; D002118:Calcium