Effect of post-training flumazenil administration on baclofen-induced amnesia in passive avoidance learning

Baclofen as a GABA-B receptor agonist and flumazenil as a benzodiazepine receptor antagonist facilitate chloride influx via GABA receptors. The aim of this study was to investigate the effect of flumazenil on baclofen-induced amnesia in passive avoidance learning in male rats. In this study, 49 male rats (200-250 gr) were randomly divided into 7 groups (n=7): non-shocked, shocked, flumazenil (0.5mg/kg, i.p.), baclofen (10 mg/kg, I.P.), and three groups which received baclofen together with flumazenil at 5, 90 and 360 min post-training. Animals were examined by shuttle box for avoidance learning and retrieval test was done 48 h after learning. The step through latency and passive avoidance response including time in dark chamber and number of entrance were recorded and analyzed. The amnesic effect of baclofen was confirmed by the results of our study. Flumazenil alone had no effect on passive avoidance memory, although 90 min after training it inhibited the baclofen-induced amnesia. It seems that flumazenil is able to antagonize the inhibitory effect of baclofen. It can be concluded that flumazenil in the elevated concentrations can affect GABA-B receptors and have long lasting effect on memory retention.