THE NMDA ANTAGONIST MEMANTINE IMPAIRS CLASSICAL EYEBLINK CONDITIONINGIN HUMANS

The present study investigated the effects of a single oral dose (30 m g) of the non-competitive N-methyl-D-aspartate (NMDA) receptor antagon ist memantine on memory and learning in human subjects. Sixteen male h ealthy volunteers participated in a double blind placebo controlled st udy. There were no significant effects of memantine on mood, attention or immediate and delayed verbal and visuospatial memory. Memantine di d, however, delay the acquisition of classical eyeblink conditioning a nd reduced the overall frequency of conditioned responses without affe cting reflex or spontaneous eyeblinks. These findings are compatible w ith the higher affinity of memantine to cerebellar as compared to fore brain tissue and demonstrate the dissociability of different memory sy stems by pharmacological tools. (C) 1997 Elsevier Science Ireland Ltd.