The inducing NO-vasodilation by chemical reduction of coordinated nitrite ion in cis-[Ru(NO(2))L(bpy)(2)](+) complex.
The synthesis of [Ru(NO(2))L(bpy)(2)](+) (bpy = 2,2'-bipyridine and L = pyridine (py) and pyrazine (pz)) can be accomplished by addition of [Ru(NO)L(bpy)(2)](PF(6))(3) to aqueous solutions of physiological pH. The electrochemical processes of [Ru(NO(2))L(bpy)(2)](+) in aqueous solution were studied by cyclic voltammetry and differential pulse voltammetry. The anodic scan shows a peak around 1.00 V vs. Ag/AgCl attributed to the oxidation process centered on the metal ion. However, in the cathodic scan a second peak around -0.60 V vs. Ag/AgCl was observed and attributed to the reduction process centered on the nitrite ligand. The controlled reduction potential electrolysis at -0.80 V vs. Ag/AgCl shows NO release characteristics as judged by NO measurement with a NO-sensor. This assumption was confirmed by ESI/MS(+) and spectroelectrochemical experiment where cis-[Ru(bpy)(2)L(H(2)O)](2+) was obtained as a product of the reduction of cis-[Ru(II)(NO(2))L(bpy)(2)](+). The vasorelaxation observed in denuded aortic rings pre-contracted with 0.1 mumol L(-1) phenylephrine responded with relaxation in the presence of cis-[Ru(II)(NO(2))L(bpy)(2)](+). The potential of rat aorta cells to metabolize cis-[Ru(II)(NO(2))L(bpy)(2)](+) was also followed by confocal analysis. The obtained results suggest that NO release happens by reduction of cis-[Ru(II)(NO(2))L(bpy)(2)](+) inside the cell. The maximum vasorelaxation was achieved with 1 x 10(-5) mol L(-1) of cis-[Ru(II)(NO(2))L(bpy)(2)](+) complex.
da Rocha
Zênis Novais
ZN
Instituto de Química da Universidade Federal da Bahia - Campus Ondina, Salvador, Bahia, Brazil.
Marchesi
Mario Sérgio Pereira
MS
Molin
Josiane Cristina
JC
Lunardi
Claure N
CN
Miranda
Katrina M
KM
Bendhack
Lusiane Maria
LM
Ford
Peter C
PC
da Silva
Roberto Santana
RS
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D004563:Electrochemistry; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D012428:Ruthenium / Q000737:chemistry*; D014664:Vasodilation / Q000187:drug effects*
D009573:Nitrites; D009942:Organometallic Compounds; D009569:Nitric Oxide; D012428:Ruthenium