Effects of nicorandil on the rhythmic contractile response of isolated miniature pig coronary artery to 3,4-diaminopyridine: comparison with nitroglycerin.
Effects of 2 antianginal agents, nicorandil and nitroglycerin, on the rhythmic contraction induced by 3,4-diaminopyridine (DAP) were investigated in the isolated coronary artery of the miniature pig. Application of 10(-2) M 3,4-DAP elicited a sustained rhythmic contraction of the artery, lasting more than 3 hr. Nicorandil significantly reduced the peak tension of the contraction phase and the tension of the relaxation phase at concentrations of 10(-6) and 10(-5) M. The cycle length and the reappearance time of the rhythmic contraction were only significantly prolonged at a concentration of 10(-5) M. Finally a concentration of 10(-4) M led to the disappearance of rhythmic contraction. Nitroglycerin (10(-8) - 10(-4) M) significantly reduced the peak tension of the contraction phase and the tension during the relaxation phase in a concentration-dependent manner. At concentrations of 10(-6) to 10(-4) M, it also greatly prolonged the reappearance time of the rhythmic contraction, but the contraction was never eliminated even at the highest concentration (10(-4) M) of nitroglycerin used. The result indicates that nicorandil has an effect on the rhythmic contraction caused by 3,4-DAP through a mechanism somewhat different from nitroglycerin.
D015761:4-Aminopyridine / Q000031:analogs & derivatives*; D000077770:Amifampridine; D000631:Aminopyridines / Q000494:pharmacology*; D000818:Animals; D003329:Coronary Vasospasm / Q000503:physiopathology*; D003331:Coronary Vessels / Q000187:drug effects; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D020108:Nicorandil; D005996:Nitroglycerin / Q000494:pharmacology*; D013552:Swine; D013556:Swine, Miniature
D000631:Aminopyridines; D009536:Niacinamide; D020108:Nicorandil; D015761:4-Aminopyridine; D005996:Nitroglycerin; D000077770:Amifampridine