Oxidative stress and NADPH oxidase participation on the hypotensive responses of [Ru(terpy)(bdq)NO+]3+ (TERPY) in spontaneously hypertensive rats (SHR)

Abstract

The hypotensive effect of the new NO donor TERPY was evaluated in Wistar (WST) and SHR after pre‐infusion with an in bolus injection of Tempol (superoxide dismutase mimetic; 30 mg/Kg) and Apocynin (NADPH oxidase inhibitor; 30mg/Kg) and the effects were compared to sodium nitroprusside (SNP) effects (35 μg/Kg). The hypotensive effect of both NO donors was increased in SHR, but only SNP increased the HR (heart rate). The Tempol infusion decreased the mean arterial pressure (MAP) in WST and SHR, but did not alter the HR and reduced the TERPY effect. In the presence of Tempol, the hypotension evoked by TERPY is not different between WST and SHR, and the SNP effect was increased in SHR. Apocynin induced hypotension was more significant in SHR, but it decreased the HR in both groups. In apocynin infused rats, the hypotension induced by TERPY was higher in SHR, but there was no difference in the effect of SNP. These results indicates that superoxide anions is involved in the difference of the hypotensive effect between Wistar and SHR and that NADPH oxidase participates in the hypotensive response of SNP but not to TERPY.