Sarcolemmal dependence of isosorbide dinitrate-induced relaxation of aortic smooth muscle.
Studies were conducted to determine if ISDN antagonizes the contractile responses to calcium of chemically-skinned aortic smooth muscle preparations. Isosorbide dinitrate relaxed intact aortic smooth muscle segments in a dose-dependent manner (0.01-100 microM). At all concentrations tested, ISDN was unable to relax triton-skinned smooth muscle preparations. However, the tension development of skinned preparations was inhibited by trifluoperazine (10 microM), a calmodulin antagonist. These results suggest that the relaxation of intact aortic smooth muscle preparations induced by ISDN is not related to an interference with calmodulin-dependent contractile events.
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007548:Isosorbide Dinitrate / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000648:ultrastructure; D012508:Sarcolemma / Q000502:physiology*; D014268:Trifluoperazine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D014268:Trifluoperazine; D007548:Isosorbide Dinitrate; D002118:Calcium