6-OHDA bilateral lesions to the amygdala abolish the memory enhancing effect of angiotensin II in rats.

The involvement of a dopaminergic projection arriving at the central amygdala (CA) in angiotensin II (AII) facilitation of affectively motivated memory was investigated in male rats. AII was given intracerebroventricularly 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 neurotoxin, 30 min before surgery rats were pre-treated intraperitoneally with 25 mg kg-1 of desmethylimipramine, an inhibitor of noradrenaline uptake. Bilateral 6-OHDA lesions to CA totally abolished the facilitatory effect of AII on the retrieval process in a passive avoidance situation, 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 to the dopaminergic projection arriving at CA.