D3 dopamine receptor mRNA expression in lymphocytes: a peripheral marker for schizophrenia?

Background: Identification of schizophrenia, a common neuropsychiatric disorder, is based on clinical examination. An easily measurable peripheral marker, which may enable a more rapid and more accurate diagnosis, is not available. A possible candidate is the D3 dopamine receptor on lymphocytes.

Objective: The D3 receptor is investigated for its clinical significance as a marker for diagnosing schizophrenia.

Methods: From eight schizophrenic patients and eight controls lymphocyte RNA was isolated. A semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) was carried out and the intensities of the specific D3 dopamine receptor bands of patients and controls were compared.

Results: No difference could be seen between the intensities of the bands from patients and controls.

Conclusion: An aberrant D3 dopamine receptor mRNA expression in lymphocytes of schizophrenics could not be demonstrated. This might be caused by down-regulation of D3 receptor production by antipsychotic drug treatment. At present, the D3 receptor seems to have no diagnostic value in schizophrenia.