LOSARTAN INFLUENCES BEHAVIORAL-EFFECTS OF ANGIOTENSIN II(3-7) IN RATS

We have previously shown that angiotensin II(3-7) [Ang II(3-7)] stimul ates behavioural activity of rats similar to angiotensin II (Ang II). The involvement of AT(1) angiotensin receptors in stimulating the beha vioural activity of rats, using their selective ligand losartan (DUP 7 53), was examined. Ang LI(3-7), given intracerebroventricularly (ICV) at a dose of 1 nmol, significantly enhanced recall of a passive avoida nce behaviour, object recognition, learning of conditioned avoidance r esponses (CARs) and apomorphine (I mg kg(-1), i.p.) stereotypy. Losart an (1 mu g, ICV) did not alter any of the behaviours except for that m easuring anxiety which was diminished both, in peptide treated and in control rats. On the other hand, losartan abolished Ang II(3-7) facili tation of recall of the passive avoidance, object recognition and the increase in apomorphine stereotypy. Losartan did not influence the inc reased rate of CARs acquisition after the peptide. None of the treatme nts significantly changed locomotor activity estimated in an open held . These data point to some involvement of AT(1) angiotensin receptors in the behavioural activity of Ang LI(3-7). (C) 1997 The Italian Pharm acological Society.