Effect of bilateral intra-PVN infusion of VIPER on mean arterial blood pressure (MAP, in millimeters of mercury) and cardiac hypertrophy in WKY and SHR rats. (A) SHR + CP group had significantly increased MAP when compared to WKY + CP rats. Interestingly, infusion of VIPER in PVN of SHR rats for 14 days resulted in significant decrease in MAP, starting from day 4 of VIPER infusion; (B) heart weight to body weight ratio; and (C) mRNA expression of atrial natriuretic peptide (ANP) in tissue obtained from left ventricle. Values are mean ± SE; n = 8/group for mRNA analysis and n = 14 for MAP. *P <0.05 SHR + CP versus WKY + CP; #P < 0.05 SHR + VIPER versus SHR + CP; ***P <0.001 : ANP, Atrial Natriuretic Peptide; CP, control peptide; MAP, mean arterial pressure; PVN, paraventricular nucleus; SHR, spontaneously hypertensive rat; TLR4, Toll-like receptor 4; VIPER, viral inhibitory peptide of TLR4; WKY, wistar-Kyoto.