Recent progress in angiotensin II type 2 receptor research in the cardiovascular system

Angiotensin II (Ang II) plays an important role in regulating cardiovascular hemodynamics and structure. Multiple lines of evidence have suggested the existence of Ang II receptor subtypes, and at least 2 distinct receptor subtypes have been defined on the basis of their differential pharmacological and biochemical properties and designated as type 1 (AT(1)) and type 2 (AT(2)) receptors. To date, most of the known effects of Ang II in adult tissues are attributable to the AT(1) receptor. Recent cloning of the AT(2) receptor contributes to reveal its physiological functions, but many functions of the AT(2) receptor are still an enigma. AT(1) and AT(2) receptors belong to the 7-transmembrane, G protein-coupled receptor family, However, accumulating evidence demonstrates that the function and signaling mechanisms of these receptor subtypes are quite different, and these receptors may exert opposite effects in terms of cell growth and blood pressure regulation. We will review the role of the AT(2) receptor in the cardiovascular system and the molecular and cellular mechanisms of AT(2) receptor action.