6-OHDA lesions to the central amygdala abolish angiotensins facilitation of object recognition in rats

1. We have previously reported that the dopaminergic projection from A10 ventral tegmental neurons and A9 neurons of substantia nigra to the central amygdala (CA) is, in part, responsible for the facilitatory effect of angiotensin II (AII) and its 3-7 fragment [AII(3-7)] on the retrieval of information in memory that is motivated affectively. 2. In this study, the influence of both angiotensins, given intracerebroventricularly at the dose of 1 nmol each in rats lesioned with 6-OHDA to CA, on recognition memory, was tested. 3. AII and its 3-7 fragment significantly improved object recognition in sham-operated groups of rats. Bilateral 6-OHDA lesions to CA totally abolished the facilitatory effect of both angiotensins on object recognition. As insignificant increase of spontaneous locomotor activity in rats lesioned to CA did not interfere with the cognitive effect of AII and AII(3-7). 4. These results suggest that the dopaminergic projection at the CA takes part in the facilitatory effect of angiotensins on recognition memory.