GENETIC DELETION AND OVEREXPRESSION OF ANGIOTENSIN-II RECEPTORS

Angiotensin II receptors are essential components of the renin-angiote nsin system transducing angiotensin II mediated signals across the pla sma membrane of many cell types in the cardiovascular system. To date, three subtypes of angiotensin II receptors have been identified by mo lecular cloning, termed angiotensin II type 1 (AT(1A), AT(1B)) and typ e 2 (AT(2)) receptors. This review focuses on recent transgenic animal models which have been generated to study the in vivo significance of angiotensin receptor diversity. AT(1A) receptors are the major blood pressure regulators and have a potent growth-stimulatory effect on car diac myocytes in vivo. The AT(1B) receptor subtype may participate in the control of vascular tone if AT(1A) receptors are absent. AT(2) rec eptors are abundantly expressed during embryonic development and may a lso play a role in blood pressure regulation by influencing vascular d evelopment and differentiation.