title: Modulation of extraluminally induced vasoconstrictions by endothelium-derived nitric oxide in the canine basilar artery.
abstract: The present study was undertaken to investigate the role of endothelium in extraluminally induced vasospasm of the cerebral artery using isolated perfused canine basilar arteries. The extraluminal applications of high K+ and prostaglandin F2 alpha (PGF2 alpha) induced concentration-dependent vasoconstriction. Both constrictive responses were significantly enhanced by denuding endothelium. Additionally, the responses in the endothelium-intact arteries were markedly augmented by intraluminal perfusion with NG-monomethyl-L-arginine (L-NMMA). These results suggest that the inhibition of nitric oxide (NO) synthase in endothelium enhances increase in transmembrane Ca(2+)-influx which is a common constrictive mechanism to the vasoconstrictors. The augmentative action induced by L-NMMA was inhibited by intraluminal perfusion of L-arginine, but not by D-arginine. Furthermore, the augmentation was not observed in the arteries without endothelium. These results suggest that the endothelium may have a great significance on responsiveness to extraluminal vasoactive substances and that endothelium-derived NO may modulate the extraluminally induced vasoconstriction which is responsible for cerebral vasospasm after subarachnoid hemorrhage.
authors.affiliation: Department of Pharmacology, Dainippon Pharmaceutical Co. Ltd., Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Minato
authors.forename: M
authors.initials: M
authors.lastname: Hashizume
authors.forename: Y
authors.initials: Y
authors.lastname: Masuda
authors.forename: K
authors.initials: K
authors.lastname: Hosoki
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001488:Basilar Artery / Q000187:drug effects* / Q000201:enzymology; D015237:Dinoprost / Q000494:pharmacology; D004285:Dogs; D004730:Endothelium, Vascular / Q000378:metabolism / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019001:Nitric Oxide Synthase; D011188:Potassium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*; D019323:omega-N-Methylarginine
chemical_list: D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D015237:Dinoprost; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D011188:Potassium