STATE-DEPENDENT RETENTION EFFECTS WITH XYLAZINE (ROMPUN) IN PASSIVE-AVOIDANCE CONDITIONING

To determine whether xylazine (Rompun), an alpha-2 adrenergic receptor agonist with sedative/analgesic properties, influences memory processes, rats were trained in a passive-avoidance task either before or after receiving the drug. Experiment 1 found that subjects who had received a 3-cc/kg Rompun injection (IP) 60 sec before training showed impaired retention when tested 24 h later in a mismatched-drug condition. This impairment, however, was reversed in an identically trained group that received a second injection of the drug 60 sec before testing. Thus, the amnestic effects of pretraining injections of Rompun are due to induction of state-dependent retention (SDR). Experiment 2 was designed to determine whether SDR would occur with alternative drug-to-training intervals. Nine possible intervals were sampled, ranging from drug administration 90 sec pretraining to 30 min posttraining. No evidence of retrograde effects were obtained: under the conditions employed, the drug must be administered at least 60 sec prior to training for memory impairment to occur.