State dependent learning produced by post trial intrathoracic administration of sodium pentobarbital

Abstract

The state dependent learning paradigm was used with a one-trial, passive avoidance task. Forty male rats were equally distributed among four groups: One group received intrathoracic injections of sodium pentobarbital immediately after the acquisition trial and immediately before the retention test trial; a second group received equivalent injections of 0.9% saline; a third group was drugged after acquisition and given saline prior to retention testing and the fourth group was given saline after acquisition and drug prior to retention testing. All groups showed increased latencies on the retention trial but marked group differences in retention test latencies indicate that there was significantly more retention of training when drug states were the same during the memory storage interval and the memory retrieval interval. Intrathoracic injection proved to be a practical substitute for intravenous injection in assuring rapid onset of drug effect.