Cognitive enhancing actions of PD123177 detected in a mouse habituation paradigm.

The anxiolytic-like and cognitive enhancing potential of PD123177, a non-peptide with selectivity for the angiotensin II-2 receptor recognition site, was assessed in a mouse light/dark aversion test and habituation test, respectively. PD123177 (0.01 ng kg-1 to 1.0 mg kg-1 i.p.) failed to alter the behavioural repertoire of animals in the light/dark aversion test. In contrast, daily administration of PD123177 (10.0 ng kg-1 i.p. b.d.) enhanced the performance of mice in a habituation test. In addition, PD123177 overcame the cognitive impairment induced by the administration of scopolamine (0.25 mg kg-1 i.p.). Such findings indicate for the first time a functional role for the angiotension II-2 receptor and further implicate the angiotensin system in the modulation of cognitive processes.