A peptide vasoconstrictor; selectively binds to the AT2 over AT1 receptors (IC50s = 48.6 and >1,000 nM, respectively, in HEK293 cells expressing rat receptors); binds to AT4 receptors in bovine aortic endothelial cell membranes (IC50s = 1.6 nM); induces a positive chronotropic effect in isolated rat right atria (EC50 = 4.68 μM); increases MAP in vivo in rats (1 pmol, i.c.v.); increases latency to withdrawal in a tail-flick test in rats (vlPAG microinjection)