6-OHDA BILATERAL LESIONS TO THE AMYGDALA ABOLISH THE MEMORY-ENHANCINGEFFECT OF ANGIOTENSIN-II IN RATS

The involvement of a dopaminergic projection arriving at the central a mygdala (CA) in angiotensin II (AII) facilitation of affectively motiv ated memory was investigated in male rats. AII was given intracerebrov entricularly at a dose of 1 nmol, 15 min before retention testing in a passive avoidance situation after bilateral 6-OHDA lesions to CA. In order to protect noradrenergic neurones against destruction by neuroto xin, 30 min before surgery rats were pre-treated intraperitoneally wit h 25 mg kg(-1) of desmethylimipramine, an inhibitor of noradrenaline u ptake. Bilateral 6-OHDA lesions to CA totally abolished the facilitato ry effect of AII on the retrieval process in a passive avoidance situa tion, but had no influence on the spontaneous psychomotor activity of rats. These results suggest that the anatomical substrate facilitating the retrieval of the information activity of AII is closely related t o the dopaminergic projection arriving at CA. (C) 1998 The Italian Pha rmacological Society.