Hypertension and RhoA/Rho-kinase signaling in the vasculature: highlights from the recent literature.

Under normal conditions, contractile activity in vascular smooth muscle is initiated by either receptor activation (norepinephrine, angiotensin II, etc.) or by a stretch-activated mechanism. After this activation, several signaling pathways can initiate a Ca2+-calmodulin interaction to stimulate phosphorylation of the light chain of myosin. Ca2+ sensitization of the contractile proteins is signaled by the RhoA/Rho-kinase pathway to inhibit the dephosphorylation of the light chain by myosin phosphatase thereby maintaining force generation. In opposition to force generation, NO is released from endothelial cells and causes vasodilation through inhibition of the RhoA/Rho-kinase signaling pathway. This brief review will highlight recent studies demonstrating a role for the RhoA/Rho-kinase signaling pathway in the increased vasoconstriction characteristic of hypertension.