Angiotensin II (3-8) is an endogenous C-terminal fragment of the peptide vasoconstrictor angiotensin II .1 It selectively binds to the angiotensin 2 (AT2) over AT1 receptors (IC50s = 48.6 and >1,000 nM, respectively, in HEK293 cells expressing rat receptors). It also binds to AT4 receptors in bovine aortic endothelial cell membranes (IC50 = 1.6 nM).2 Angiotensin II (3-8) induces a positive chronotropic effect in isolated rat right atria (EC50 = 4.68 μM) and increases mean arterial pressure (MAP) in vivo in rats when administrated intracerebroventricularly at a dose of 1 pmol.3,4 It also increases latency to withdrawal in a tail-flick test in rats when administered by microinjection into the ventrolateral periaqueductal gray (vlPAG).5
1.Bosnyak, S., Jones, E.S., Christopoulos, A., et al.Relative affinity of angiotensin peptides and novel ligands at AT1 and AT2 receptorsClin. Sci. (Lond.)121(7)297-303(2011) 2.Bernier, S.G., Bellemare, J.M., Escher, E., et al.Characterization of AT4 receptor from bovine aortic endothelium with photosensitive analogues of angiotensin IVBiochemistry37(12)4280-4287(1998) 3.Li, Q., Zhang, J., Pfaffendorf, M., et al.Direct positive chronotropic effects of angiotensin II and angiotensin III in pithed rats and in rat isolated atriaBr. J. Pharmacol.118(7)1653-1658(1996) 4.Wright, J.W., Jensen, L.L., Roberts, K.A., et al.Structure-function analyses of brain angiotensin control of pressor action in ratsAm. J. Physiol.257(6 Pt. 2)R1551-R1557(1989) 5.Guethe, L.M., Pelegrini-da-Silva, A., Borelli, K.G., et al.Angiotensin (5-8) modulates nociception at the rat periaqueductal gray via the NO-sGC pathway and an endogenous opioidNeuroscience231315-327(2013)