Our findings that HMGB1 levels were increased both in the circulation and in the PVN together with increase in PICs ,iNOS and plasma NE suggest that TLR4 participates in the inflammatory process associated with hypertension leading to sustained activation of NFκB pathway to produce inflammatory alterations, sympathoexcitation, and cardiac hypertrophy in SHR rats. This evidence concerns the gene NOS2 and cardiac hypertrophy.