Cardiovascular effects of the angiotensin type 2 receptor

The angiotensin type 2 receptor, AT(2)R, has been described as having opposite effects to the angiotensin type 1 receptor, AT(1)R. Although the quantities of the AT(2)R found in the adult are low, its expression rises in pathological situations. The AT(2)R has three major signaling pathways: activation of serine/threonine phosphatases (promoting apoptosis and antioxidant effects), activation of the bradykinin/NO/cGMP pathway (promoting vasodilation), and activation of phospholipase A2 (associated with regulation of potassium currents). The AT(2)R appears to have effects in vascular remodeling, atherosclerosis prevention and blood pressure lowering (when associated with an AT(1)R inhibitor). After myocardial infarction, the AT(2)R appears to decrease infarct size, cardiac hypertrophy and fibrosis, and to improve cardiac function. However, its role in the heart is controversial. In the kidney, the AT(2)R promotes natriuresis. Until now, treatment directed at the renin-angiotensin-aldosterone system has been based on angiotensin-converting enzyme inhibitors or angiotensin type 1 receptor blockers. The study of the AT(2)R has been revolutionized by the discovery of a direct agonist, C21, which promises to become part of the treatment of cardiovascular disease. (C) 2013 Sociedade Portuguesa de Cardiologia. Published by Elsevier Espana, S.L.U. All rights reserved.