The non-peptidic angiotensin II receptor subtype selective antagonists, DuP 753 and PD123177, were used to characterize angiotensin II receptor binding sites in the rat brain. Competitive receptor autoradiography with 125I-Sar1-Ile8 angiotensin II defined a regional distribution of binding sites that were sensitive to either DuP 753 (designated AIIα subtype) or PD123177 (designated AIIβ subtype). Whereas most brain nuclei could be assigned to a category containing a predominant subtype, a multiple receptor subtype analysis indicated that some regions are homogeneous, while others contain a mixture of both AIIα and AIIβ subtypes.

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-[Sar1, Ile8]AII (125I-SIAII) binding in many brain nuclei (IC50 = 20-30 nM), but was a weak competitor at remaining sites (IC50 > 10-4 M). DuP 753 sensitive binding sites (designated AIIα subtype) correspond with areas where binding is inhibited by sulfhydryl reducing agents, whereas DuP 753 insensitive sites (AIIβ) correspond with areas where binding is not inhibited by sulfhydryl reducing agents.