Vascular angiotensin AT2 receptors in hypertension and ageing

1. Angiotensin II (Ang II) acts on both subtype 1 receptors (AT1R) and subtype 2 receptors (AT2R). AT1R stimulation mediates all of the classical actions of Ang II including vasoconstriction and cardiovascular hypertrophy. By contrast, AT2R stimulation is thought to exert a counter-regulatory effect on AT1R and exert direct vasodilatation and antigrowth effects. 2. In this brief review, the vascular effects of AT2R are reviewed in the context of recent data relating to hypertension and ageing. 3. In particular the vascular AT2R phenotype in isolated mesenteric arteries may switch from that of relaxation to contraction in hypertension or ageing and this AT2R contractile phenotype can be converted to relaxation, at least with chronic antihypertensive treatment in spontaneously hypertensive rats. 4. In vivo data pertaining to hypertension and ageing are consistent with vasodilator and antiremodelling effects of AT2R.