STRAIN-DEPENDENT EFFECTS OF POST-TRAINING GABA RECEPTOR AGONISTS AND ANTAGONISTS ON MEMORY STORAGE IN MICE

Post-training administration of the GABA-A and GABA-B receptor agonist s muscimol and baclofen dose-dependently impaired retention of an inhi bitory avoidance response in C57 mice, while improving memory consolid ation in the DBA strain. By contrast, picrotoxin (blocker of GABA-acti vated ionophores), bicuculline (GABA-A antagonist) and CGP 35348 (GABA -B antagonist) dose-dependently improved retention in C57 mice and imp aired it in DBA mice. These effects cannot be ascribed to non-specific actions of the drugs on retention performance, as the latencies durin g the retention test of those mice that had not received footshock dur ing the training were not lengthened by the post-training drug adminis tration. The effects on retention performance induced by GABA agonists and antagonists are probably due to an effect on memory consolidation , since they are observed when the drugs are given at short, but not a t long, intervals after training. These results are discussed in terms of possible interaction of GABA systems with endogenous opioid and do pamine systems, whose activation has been shown to produce strain-depe ndent effects on memory processes. The possible utilization of these r esults for a genetic behavioral approach with recombinant inbred (RI) mice is also considered.