Schizophrenia: elevated mRNA for dopamine D2(Longer) receptors in frontal cortex

Because dopamine D2 receptors are the primary targets for antipsychotic dru gs, including clozapine and quetiapine, and because some studies have found D2 receptors to be elevated in schizophrenia, we examined the mRNA of thre e forms of the D2 receptor, particularly the new form of the dopamine D2 re ceptor, D2(Longer) in post-mortem brains from patients who died with schizo phrenia. Using quantitative competitive RT-PCR (reverse transcriptase-polym erase chain reaction), the D2(Longer) mRNA was higher in the frontal cortex , compared to control tissues. The mRNA concentration of D2(Long) and D2(Sh ort) was also higher in the frontal cortex, compared to control tissues. Al though most of the schizophrenia patients had received different antipsycho tic drugs for varying periods of time, the mRNA of D2(Longer) as well as th at for D2(Long) and D2(Short). in such medicated tissues was similar to tha t in a frontal cortex tissue from a patient who had reliably never received antipsychotic drugs. It is possible, therefore, that the elevation of the mRNAs for D2(Longer) D2(Long) and D2(Short) in the frontal cortex may be re lated to the disease of schizophrenia itself. (C) 2001 Elsevier Science B.V . All rights reserved.