TITLE:
Dopamine receptor D3R and D4R mRNA levels in peripheral lymphocytes in patients with schizophrenia correlate with severity of illness
AUTHORS:
Mitsuhiko Kawano, Ken Sawada, Emi Tsuru, Makoto Nishihara, Kunio Kato, William G. Honer, Shinji Shimodera
KEYWORDS:
Dopamine receptor D3R; Dopamine Receptor D4R; Schizophrenia; RT-PCR; Lymphocyte; Cognitive Function
JOURNAL NAME:
Open Journal of Psychiatry,
Vol.1 No.2,
July
12,
2011
ABSTRACT: Schizophrenia is a disease that affects many areas of the brain. The dopamine hypothesis is one of the most widely-accepted ideas in the pathophysiology of schizophrenia. Besides alterations in the dopaminergic system in the central nervous system, there have been several reports of changes in dopaminergic systems in the peripheral blood of schizophrenic patients. Several reports have shown that dopamine receptor expression by lymphocytes is altered in patients with schizophrenia, but the results have been conflicting. We therefore re-assessed D3R and D4R mRNA levels in 11 patients with schizophrenia and 12 healthy subjects and correlated levels with severity of symptoms. D3R and D4R expression in lymphocytes and granulocytes was measured by quantitative RT-PCR and the severity of symptoms and cognitive impairment were assessed using the PANSS and BACS-J. There were no significant differences in mean D3R or D4R mRNA levels in lymphocytes from schizophrenic patients and controls and no significant difference in mean D4R mRNA levels in granulocytes (D3R mRNA undetectable). In patients with schizophrenia, D3R expression was inversely correlated with the total PANSS score (r = 0.768, p = 0.009), while D4R expression was positively correlated with working memory scales (r = 0.895, p = 0.001). In conclusion, these results imply that lymphocyte D3R and D4R are involved in the mechanisms of the disorder and could be used as target markers in the treatment of schizophrenia.