Reversal of ECS-induced amnesia by post-ECS injections of amphetamine

Water deprived rats were trained to drink from a water spout within an apparatus on each of 2 days. On the third day, passive avoidance of the spout was induced by giving the animal a 0.3 sec, 5 mA footshock after 1 lick at the spout. A test for retention of the avoidance learning was given 48 hr following training. ECS administered through cortical electrodes at 15 sec following the footshcok impaired retention. The amnesia was attenuated when amphetamine (1 mg/kg) was injected immediately but not at 6 hr following the ECS. In a second experiment, attentuation of amnesia by amphetamine was not found when the ECS occured at 4 sec instead of 15 sec following the footshock. The results are interpreted in terms of reactivation by amphetamine of a consolidation process that was interrupted by ECS.