Pre-training administration of anesthetic ketamine differentially affects rats' spatial and non-spatial recognition memory

There is poor experimental evidence concerning the effects of anesthetic doses of the non-competitive NMDA receptor antagonist ketamine on rodents' memory abilities. The present study was designed to investigate a) the long-term consequences of anesthetic ketamine on rats' non-spatial and spatial recognition memory; b) to evaluate whether or not these effects are related to the hypothermic properties of ketamine and c) to detect when the (amnestic) effects of ketamine on recognition memory were extinguished. For this purpose, the object recognition and the object location task were selected. Pre-training administration of ketamine (100 mg/kg; i.p.) disrupted animals' performance in the object location task and to some extent also in the object recognition paradigm indicating that anesthetic ketamine impaired both spatial and non-spatial recognition memory. Hypothermia-induced by this NMDA receptor antagonist and the type (spatial vs. non-spatial) of the behavioral paradigm utilized seem to affect rats' recognition memory recovery.