Discrimination of angiotensin II receptor subtype distribution in the rat brain using non-peptidic receptor antagonists

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-Sar 1-Ile 8 angiotensin II defined a regional distribution of binding sites that were sensitive to either DuP 753 (designated AII α subtype) or PD123177 (designated AII β 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 AII α and AII β subtypes.