title: Nitric oxide synthase/guanylate cyclase pathway modulates the rat vas deferens contractility induced by phenylephrine.
abstract: The involvement of the nitric oxide synthase/soluble guanylate cyclase pathway on the modulation of phenylephrine-induced contractility in the rat vas deferens was investigated. Phenlylephrine-concentration response curves were obtained in absence and in presence of inhibitors, N(G)-Nitro-L-arginine (L-NOARG), NG-Nitro-L-arginine methyl esther (L-NAME) or N(G)-monomethyl-L-arginine (L-NMMA) or GC inhibitior, 1H-(1,2,4)-oxadiaziol-(4,3-a)quinoxalin-1-one (ODQ) or nitric oxide donor, 3-morpholinosydnonimine hydrochloride (SIN-1) alone or together with L-NMMA or ODQ. Both nitric oxide synthase and GC inhibitors reduced the Phe-Emax. SIN-1 alone did not change phenylephrine-induced responses and it could reverse the L-NMMA effect but not ODQ effect. The reduction of the phenylephrine-induced contractility obtained in consequence of the inhibition of the nitric oxide/GC pathway suggest that, in the rat vas deferens, despite its well identified relaxant properties, nitric oxide potentiates the contractility induced by adrenergic stimulation.
authors.affiliation: Unit of Pharmacology and Pharmacotoxicology, Faculty of Pharmacy, University of Lisbon, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Pinto
authors.forename: Helder
authors.initials: H
authors.lastname: Mota-Filipe
authors.forename: Beatriz Silva
authors.initials: BS
authors.lastname: Lima
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010656:Phenylephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014649:Vas Deferens / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D010656:Phenylephrine; D019323:omega-N-Methylarginine; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D019331:NG-Nitroarginine Methyl Ester