L-arginine induces relaxation of human uterine artery with both intact and denuded endothelium.
The effect of L-arginine on isolated human uterine artery rings was investigated. L-Arginine, but not D-arginine, induced concentration-dependent relaxation. Removal of the endothelium enhanced the relaxant effects of L-arginine. Methylene blue and dexamethasone non-competitively inhibited L-arginine-induced relaxation, while NG-monomethyl-L-arginine competitively antagonized the response to L-arginine. Calmidazolium did not affect relaxation evoked by L-arginine. The dissociation constants obtained for L-arginine and NG-monomethyl-L-arginine in intact rings were not significantly different from those in endothelium-denuded rings. It is concluded that the relaxation induced by L-arginine in human uterine artery is mediated by non-endothelial nitric oxide production. We suggest that the NO synthase mediating the L-arginine-induced relaxation is an inducible type.
Department of Pharmacology, University Medical Center, Medical Faculty, Belgrade, Yugoslavia.
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Jovanović
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Grbović
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Tulić
D001120:Arginine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001158:Arteries / Q000187:drug effects; D002147:Calmodulin / Q000037:antagonists & inhibitors; D003907:Dexamethasone / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D008751:Methylene Blue / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D012039:Regional Blood Flow / Q000187:drug effects; D013237:Stereoisomerism; D014599:Uterus / Q000098:blood supply; D019323:omega-N-Methylarginine
D002147:Calmodulin; D007093:Imidazoles; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; C031938:calmidazolium; D003907:Dexamethasone; D001120:Arginine; D008751:Methylene Blue