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

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.

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

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.

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

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.