Update on the role of the AT2 receptor

Purpose of review The renin-angiotensin system is a coordinated hormonal cascade important to the regulation of the renal sodium excretion and blood pressure. The major effector peptide, angiotensin II, binds two major receptors, AT(1) and AT(2). While the majority of angiotensin II actions are mediated via the AT(1) receptor, evidence has accumulated that the AT(2) receptor opposes the AT(1) receptor, especially by inducing vasodilation instead of vasoconstriction. Recent findings During the past year, the evidence for an AT(2) receptor microvascular dilator action has been presented that is mediated by nitric oxide (NO) generation in a bradykinin-dependent or independent manner. Although the AT(2) receptor is expressed in renal proximal and distal tubules and vasculature, and AT(2) receptor stimulation induces a bradykinin/NO pathway within the kidney, little information is available concerning AT(2) receptor regulation of renal function and sodium excretion. From studies reported this year, the AT(2) receptor appears to be protective against ischemic renal injury. Summary The AT(2) receptor represents a potentially important area of investigation with therapeutic applications in the future.