Angiotensin II receptor subtypes in the rat brain

The non-peptide angiotensin II (AII) receptor subtype selective antagonist, DuP 753, was used to characterize AII receptor binding sites in the rat brain. DuP 753 competed for specific 125I-[Sar 1, Ile 8]AII ( 125I-SIAII) binding in many brain nuclei (IC 50 = 20−30 nM), but was a weak competitor at remaining sites (IC 50 > 10 −4 M). DuP 753 sensitive binding sites (designated AII α subtype) correspond with areas where binding is inhibited by sulfhydryl reducing agents, whereas DuP 753 insensitive sites (AII β) correspond with areas where binding is not inhibited by sulfhydryl reducing agents.