title: Endothelial prostanoids involved in the relaxation produced by acetylcholine in the human pulmonary artery.
abstract: In ring preparations of human pulmonary artery contracted with noradrenaline (NA), the application of acetylcholine (ACh) enhanced the tension, and withdrawal produced a large relaxation which was sustained for about 10 min and required over 20 min for recovery; the latter relaxation appeared only in the endothelium-intact preparation. Indomethacin increased the amplitude of NA contractions, changed the ACh-induced contraction to relaxation, and inhibited the ACh-induced sustained relaxation. Nitroarginine increased the amplitude of NA and ACh-induced contractions, with no significant change in the ACh-induced sustained relaxation. These effects of indomethacin and nitroarginine were observed only in the endothelium-intact preparations. In NA-contracted preparations, exogenously applied prostaglandin I2 (PGI2) produced relaxation. Thus, in human pulmonary arteries, NA and ACh activities release vasodilator prostanoids and nitroarginine-sensitive EDRF from the endothelium, and initiate direct contractile actions to smooth muscle. The prostanoid-induced relaxation is sustained for a long time after the withdrawal of ACh stimulation and can be mimicked by exogenously-applied PGI2.
authors.affiliation: Department of Physiology I, Nagoya City University Medical School, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Zhang
authors.forename: H
authors.initials: H
authors.lastname: Niwa
authors.forename: A
authors.initials: A
authors.lastname: Masaoka
authors.forename: Y
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D004730:Endothelium, Vascular / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007213:Indomethacin / Q000008:administration & dosage; D008875:Middle Aged; D009126:Muscle Relaxation / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D019335:Nitroarginine / Q000008:administration & dosage; D011188:Potassium / Q000737:chemistry; D011453:Prostaglandins / Q000502:physiology*; D011651:Pulmonary Artery / Q000502:physiology*; D012964:Sodium / Q000737:chemistry; D014664:Vasodilation / Q000502:physiology*
chemical_list: D011453:Prostaglandins; D019335:Nitroarginine; D009569:Nitric Oxide; D012964:Sodium; D000109:Acetylcholine; D011188:Potassium; D007213:Indomethacin