Efficacy of clozapine compared with other antipsychotics in preventing NMDA-antagonist neurotoxicity.

The focus of this article will be on toxic symptoms associated with blockade of the N-methyl-D-aspartate (NMDA) subtype of the glutamate receptor. We have been studying two parallel phenomena: NMDA-antagonist neurotoxicity (NAN) in rats and NMDA-antagonist psychotogenicity (NAP) in humans. These phenomena have a common denominator--NMDA receptor hypofunction, which is putatively a mechanism operative in schizophrenia. We have found that the NAN reaction in rats can be prevented by specific drugs that prevent NAP in humans and by certain antipsychotic agents, including clozapine, that ameliorate symptoms in schizophrenia. By studying mechanisms by which clozapine prevents the NAN reaction in rats, we hope to gain insight into mechanisms by which clozapine or other atypical antipsychotics ameliorate symptoms in schizophrenia.