Cation Transport Systems

In addition to influencing signaling pathways associated with cell growth and inflammation, ROS modulate intracellular Ca2+ concentration ([Ca2+].), a major determinant of vascular contraction. Superoxide and H2O2 increase [Ca2+]i in VSMCs and endothelial cells.109 These effects have been attributed to redox-dependent inositol-trisphosphate-induced Ca2+ mobilization, increased Ca2+ influx, and decreased activation of Ca2+-ATPase.109110 Plasma membrane K+ channels in VSMCs that control a hyperpolarization-elicited relaxation are opened by mechanisms associated with thiol oxidation by ROS.99 100 110 These redox-regulated Ca2+ processes may be more important in stress responses than in receptor-mediated signaling by growth factors or cytokines and may play a role in altered vascular contractility in hypertension. In fact contractile responses to H2O2 are exaggerated in arteries from SHR compared with normotensive counterparts,111 suggesting that in addition to impaired endothelium-dependent vasodilation (due to increased quenching of NO by *O2-), redox-sensitive Ca2+ changes could contribute to altered vascular tone in hypertension.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

Get My Free Ebook

Post a comment