title: [Endothelium-derived relaxation of canine uterine artery and arachidonic acid metabolism].
abstract: Vascular responses to acetylcholine (ACh) and calcium ionophore A23187 were studied in the rings of the canine uterine arteries. Using uterine arteries of mature female mongrel dogs, ring-form specimens were prepared under a microscope. According to the Magnus' method the specimen was vertically fixed in Krebs-Henseleit solution and with a force-displacement transducer the isometric tension was determined. ACh and A23187 caused dose-dependent relaxation in the control, but it did not cause a response in endothelium-denuded preparations during contractions evoked by 3 X 10(-7)M norepinephrine. When pretreated with indomethacin (3 X 10(-6)M), a cyclooxygenase inhibitor, the maximal relaxation response induced by ACh was 73.35 +/- 14.53%, and pD2 values of 7.09 +/- 0.54, showing no difference from the untreated ones. On the other hand, preincubation with lipoxygenase inhibitors, nordihydroguaiaretic acid (NDGA) (3 X 10(-5)M) and AA861 (2 X 10(-5)M), prevented ACh-induced relaxation. The same trend was noted with the relaxation response induced by A23187. These results suggest that endothelium-derived relaxation of the canine uterine artery by ACh and A23187 may be mediated by a noncyclooxygenase metabolite(s). It was speculated that such inhibition of releasing EDRF has certain effects on the pathogenesis of toxemia and IUGR.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D001158:Arteries / Q000502:physiology; D001688:Biological Products / Q000494:pharmacology* / Q000502:physiology; D000001:Calcimycin / Q000494:pharmacology; D004285:Dogs; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D014599:Uterus / Q000098:blood supply*
chemical_list: D001095:Arachidonic Acids; D001688:Biological Products; D016718:Arachidonic Acid; D009569:Nitric Oxide; D000001:Calcimycin; D011451:Prostaglandin-Endoperoxide Synthases; D000109:Acetylcholine