Angiotensin receptors: distribution, signalling and function.

Angiotensin II (Ang II) is a multi-functional hormone that plays a major role in regulating blood pressure and cardiovascular homoeostasis. The actions of Ang II are mediated by at least two receptor subtypes, designated AT(1) and AT(2). In addition, other angiotensin receptors have been identified which may recognize other angiotensin peptide fragments; however, until now only the AT(1) and AT(2) receptor have been cloned in animals or humans. Most of the well-described actions of Ang II, such as vasoconstriction, facilitation of sympathetic transmission, stimulation of aldosterone release and promotion of cellular growth are all mediated by the AT(1) receptor. Much less is known about the function of the AT(2) receptor, but recent studies suggest that it may play a role in mediating anti-proliferation, cellular differentiation, apoptosis and vasodilatation. In this review, we discuss recent advances in our understanding of Ang II receptors, in particular, their distribution, signalling and function.