DIFFERENTIAL-EFFECTS OF KETASET ROMPUN ANESTHESIA ON HYPOTHERMIA-INDUCED RETROGRADE-AMNESIA AND ITS RECOVERY/

A nonbarbiturate anesthetic consisting of ketamine HCl (Ketaset) and x lyazine (Rompun) was administered to assess the effects of anesthesia on hypothermia-induced retrograde amnesia in Long Evans hooded and Spr ague-Dawley albino rats. Results from Experiment la indicate that this anesthetic does not attenuate retrograde amnesia, and the findings fr om Experiment 1b suggest that awakening from Ketaset/Rompun anesthesia at normal body temperature (following administration of deep body coo ling) does not attenuate the resulting hypothermia-induced retrograde amnesia. Experiment 2 demonstrated that various delays between trainin g and hypothermia resulted in a temporal gradient that was the same fo r animals cooled while either conscious or under anesthesia. The resul ts of Experiment 3 showed that rats made amnesic while under anesthesi a did not recover the target memory if given a recooling treatment, bu t rats that were made amnesic while conscious did recover the memory w ith the same reminder treatment. These findings indicate that the cons cious processing of stimuli associated with hypothermia treatment is n ot necessary in inducing hypothermia-induced retrograde amnesia, but t hat conscious processing is an important factor if the amnesia is to b e recovered with a recooling treatment. (C) 1995 Academic Press, Inc.