title: The effects of ruthenium tetraammine compounds on vascular smooth muscle.
abstract: The time course of the relaxation effect induced by a single dose (3 x 10(-6) mol/L) of trans-[Ru(NH3)4L(NO)]3+ (L=nic, 4-pic, py, imN, P(OEt)3, SO(3)(2-), NH3, and pz) species and sodium nitroprusside (4 x 10(-9) mol/L) was studied in aortic rings without endothelium and pre-contracted with noradrenaline (1 x 10(-6) mol/L). All the compounds induced a relaxing effect in the aortic rings, but the intensity and time of relaxation were different. Only the species where L=py, 4-pic, and P(OEt)3 were able to induce 100% (99-100%) of the relaxing effect during the assay. trans-[Ru(NH3)4(L)(NO)]3+ (L=SO(3)(2-) and NH3) showed the lowest relaxing effect (36 and 37%, respectively) when compared with the other compounds. Relationship was observed between the time corresponding to half of the maximum relaxation intensity observed and, respectively, k-NO, E0'[Ru(NO)]3+/[Ru(NO)]2+ in trans-[Ru(NH3)4(L)(NO)]3+ species and E0'Ru(III)/Ru(II) in trans-[Ru(NH3)4(L)(H2O)]3+ ions. These relationships strongly suggested that the NO liberation from the reduced nitrosyl complexes was responsible for the observed relaxation.
authors.affiliation: Departamento de Química Inorgânica, Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
authors.forename: P G
authors.initials: PG
authors.lastname: Zanichelli
authors.forename: H F G
authors.initials: HF
authors.lastname: Estrela
authors.forename: R C
authors.initials: RC
authors.lastname: Spadari-Bratfisch
authors.forename: D M
authors.initials: DM
authors.lastname: Grassi-Kassisse
authors.forename: D W
authors.initials: DW
authors.lastname: Franco
mesh_terms: D000588:Amines / Q000494:pharmacology*; D000818:Animals; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D017975:Ruthenium Compounds / Q000494:pharmacology*
chemical_list: D000588:Amines; D017975:Ruthenium Compounds; D009569:Nitric Oxide