MK-801 induces a low intensity conditioned taste aversion.

N-methyl-D-aspartate (NMDA) receptor antagonists are often used to assess the role of NMDA receptors in learning and memory processes. However, few studies have explored the possibility that the antagonists may induce a conditioned aversion when administered following flavor consumption. We report five experiments with rats intended to evaluate the MK-801 capacity to induce conditioned taste aversion. Our findings suggest that: i) MK-801 produces a low-intensity aversion following repeated pairings with saccharin (Experiments 1 and 2); ii) such aversion was not the result of a non-associative process (Experiment 3); and iii) pre-exposure to MK-801 does not interact with conditioned taste aversion induced by lithium chloride (Experiments 4 and 5). These findings suggest that MK-801 induces a low-intensity aversion, although the underlying mechanisms of this aversion may differ from those of a conditioned aversion produced by lithium chloride.