An RT-PCR study of 5-HT6 and 5-HT7 receptor mRNAs in the hippocampal formation and prefrontal cortex in schizophrenia

5-Hydroxytryptamine (5-HT; serotonin) 5-HT6 receptors (5-HT6R) and 5-HT7 receptors (5-HT7R) have been implicated in schizophrenia and as targets of atypical antipsychotic drugs. We have studied the expression of these receptors in the hippocampal formation and dorsolateral prefrontal cortex (DLPFC) of 17 subjects with schizophrenia and 17 controls using reverse transcription-polymerase chain reaction (RT-PCR) with cyclophilin co-amplification. In schizophrenia, 5-HT6R mRNA was decreased in the hippocampal formation, and 5-HT7R mRNA was decreased in the dorsolateral prefrontal cortex. The mRNAs were unchanged in rats treated for 2 weeks with haloperidol, chlorpromazine, risperidone, olanzapine or clozapine. Regional decreases in 5-HT6R and 5-HT7R expression in schizophrenia may contribute to the overall serotonergic alterations which occur in the disorder, in part through their interactions with other neurotransmitter systems including glutamate and acetylcholine. (C) 2002 Elsevier Science B.V All rights reserved.