IDENTIFICATION OF ANGIOTENSIN-II RECEPTOR SUBTYPES IN HUMAN BRAIN

THE present study assessed the binding characteristics of [I-125]angiotensin II to slices of human cerebellum adhered to glass slides using quantitative receptor autoradiography. Specific [I-125]angiotensin II binding, defined by the inclusion of unlabelled angiotensin II (1.0-mu-M), was detected in the molecular layer of the cerebellum (0.09 +/- 0.02 fmol/mg tissue equivalent, mean +/- s.e.m., n = 3). The angiotensin II-2 receptor subtype selective ligand, PD123177, competed for approximately 65% of the specific binding in the molecular layer whilst the remainder of the specific binding was displaced by the angiotensin II-1 receptor subtype selective ligand, DuP753. It is concluded that angiotensin II receptor subtypes exist in human brain tissue and provide potential therapeutic sites of action.