Coronary endothelium is responsive to bradykinin and arachidonate but not to acetylcholine.
In preparations of either endothelium-rubbed or intact porcine coronary artery, in which sodium nitroprusside caused a relaxation, acetylcholine did not cause a relaxation but a contraction. Calcium ionophore A23187 and bradykinin elicited a dose-dependent relaxation in preparations with intact endothelium, while the relaxation was abolished by rubbing the endothelium. Bradykinin-induced relaxation was not inhibited by acetylsalicylic acid (10(-4) M), indomethacin (10(-6) M), and combined treatment with phentolamine (10(-6) M) and propranolol (10(-6) M). Arachidonic acid produced an endothelium-dependent contraction, which, at 10(-5) M, was followed by a slowly developing relaxation. Prostaglandin I2 caused a slight relaxation of the artery. In conclusion, endothelial cells of porcine coronary artery respond to bradykinin and A23187, presumably through a release of the endothelium-derived relaxing factor. Vasoconstrictor prostanoid(s) seem(s) to be involved in the arachidonic acid-induced contraction.
Harasawa
Y
Y
Department of Pharmacology, Upjohn Tsukuba Research Laboratories, Japan.
Kimura
M
M
Ohno
Y
Y
Hayashi
S
S
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology*; D001920:Bradykinin / Q000494:pharmacology*; D000001:Calcimycin / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects*; D011464:Epoprostenol / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007537:Isometric Contraction; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010208:Papaverine / Q000494:pharmacology; D011453:Prostaglandins / Q000096:biosynthesis; D013552:Swine
D001095:Arachidonic Acids; D011453:Prostaglandins; D009599:Nitroprusside; D016718:Arachidonic Acid; D009569:Nitric Oxide; D000001:Calcimycin; D010208:Papaverine; D011464:Epoprostenol; D000109:Acetylcholine; D001920:Bradykinin