Facilitation of memory retrieval by centrally administered catecholamine stimulating agents

Amnesia for inhibitory avoidance learning induced in mice by a post-training injection of the protein synthesis inhibitor anisomycin was alleviated in a dose-dependent fashion by introcerebroventricular injections of D-amphetamine (20 micrograms), dopamine (10, 25 and 50 micrograms) and the dopamine agonist lisuride (0.5 and 1.0 micrograms), given 5 min before the retention test. Animals which received avoidance training in a different apparatus did not show increased test latencies following drug treatment thus eliminating non-specific behavioral suppression as an explanation for the findings. Neither norepinephrine nor the norepinephrine agonist clonidine was able to reverse the amnesia. These findings indicate that central dopamine systems may play a role in the retrieval of inhibitory avoidance learning.