Notes on the acetylcholine-induced relaxation of porcine coronary arteries.
Intact and rubbed coronary arteries responded to acetylcholine (ACh) with contractions in a cumulative dose-dependent manner. The rubbed artery contracted at a lower concentration of ACh (3 x 10(-8) M) than the threshold level of the agonist in the intact artery (10(-7) M). Only in the intact artery was the second cumulative dose-response to ACh (10(-6) M) decreased by 60% (p < 0.05). Pretreatment of the intact artery with methylene blue or NG-monomethyl-L-arginine (L-NMMA) increased the contractile response to ACh. The ACh-induced increase of the cGMP level in the intact artery was eliminated by removal of the endothelial cells and by pretreatment of the artery with either methylene blue or L-NMMA. These findings indicate that the endothelial cells in the coronary artery are responsible for the ACh-induced relaxation, presumably mediated by an endothelium-derived relaxing factor.
Hashimoto
M
M
Department of Physiology, Shimane Medical University, Izumo, Japan.
Ishida
Y
Y
Sakuma
I
I
Tanaka
Y
Y
Masumura
S
S
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008751:Methylene Blue / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D011863:Radioimmunoassay; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects; D019323:omega-N-Methylarginine
D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D006152:Cyclic GMP; D000109:Acetylcholine; D008751:Methylene Blue