title: Endothelium-derived relaxation of the pregnant and nonpregnant canine uterine artery.
abstract: Vascular responses to acetylcholine (ACh) and the calcium ionophore A23187 were studied in rings of pregnant and nonpregnant canine uterine arteries. Segments were fixed vertically in Krebs-Henseleit solution, and isometric tension was measured with force-displacement transducers. In nonpregnant canine artery preparations precontracted to a stable plateau tension with norepinephrine, ACh and A23187, dose-dependent relaxation was elicited in intact rings but not in endothelium-denuded rings. This endothelium-dependent relaxation was not affected by pretreatment with indomethacin but was inhibited by pretreatment with lipoxygenase inhibitors, nordihydroguaiaretic acid and the selective 5-lipoxygenase inhibitor AA861. Therefore, relaxation appeared to be mediated by a noncycloxygenase metabolite or metabolites. Similar endothelium-dependent relaxation was also observed in pregnant canine artery preparations. The results indicate that an endothelium-derived relaxing factor might play a physiologic role in maintaining the blood flow of the uterine circulation.
authors.affiliation: Department of Obstetrics and Gynecology, Mie University School of Medicine, Tsu, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: K
authors.initials: K
authors.lastname: Kanamaru
authors.forename: Y
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Murata
mesh_terms: D000109:Acetylcholine / Q000502:physiology*; D000818:Animals; D016227:Benzoquinones / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005069:Evaluation Studies as Topic; D005260:Female; D007213:Indomethacin / Q000494:pharmacology; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D009637:Masoprocol / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D011247:Pregnancy; D011270:Pregnancy, Animal; D014599:Uterus / Q000098:blood supply*; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
chemical_list: D016227:Benzoquinones; D016859:Lipoxygenase Inhibitors; D009569:Nitric Oxide; D000001:Calcimycin; D009637:Masoprocol; C036837:2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone; D000109:Acetylcholine; D007213:Indomethacin