Endothelium-derived relaxation of the pregnant and nonpregnant canine uterine artery.
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.
Matsumoto
T
T
Department of Obstetrics and Gynecology, Mie University School of Medicine, Tsu, Japan.
Kanamaru
K
K
Sugiyama
Y
Y
Murata
Y
Y
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
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