Sarilesin, also known as [Sar1,Ile8]-angiotensin II, is a specific antagonist at angiotensin receptors. Sarilesin has multiple effects on vascular smooth muscle, including contraction of normal arteries and hypertrophy or hyperplasia of cultured cells or diseased vessels. Sarilesin activates both the NADPH and NADH oxidases, and stimulates superoxide anion formation in vascular smooth muscle cells.