Genetic deletion and overexpression of angiotensin II receptors.

Angiotensin II receptors are essential components of the renin-angiotensin system transducing angiotensin II mediated signals across the plasma membrane of many cell types in the cardiovascular system. To date, three subtypes of angiotensin II receptors have been identified by molecular cloning, termed angiotensin II type 1 (AT1A, AT1B) and type 2 (AT2) receptors. This review focuses on recent transgenic animal models which have been generated to study the in vivo significance of angiotensin receptor diversity. AT1A receptors are the major blood pressure regulators and have a potent growth-stimulatory effect on cardiac myocytes in vivo. The AT1B receptor subtype may participate in the control of vascular tone if AT1A receptors are absent. AT2 receptors are abundantly expressed during embryonic development and may also play a role in blood pressure regulation by influencing vascular development and differentiation.