Effects of haloperidol on the expression of lymphocyte dopamine receptor mRNAs in the rat

1. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to inv estigate the effects of haloperidol treatment (1 mg/kg/day for 2, 7 or 21 c onsecutive days) on the expression of D1B and D3 dopamine receptor mRNAs in the rat lymphocytes. 2. The expression of D1B receptor mRNA was significantly decreased after 2 days of treatment and progressively returned toward basal values at the end of treatment. Conversely, haloperidol failed to modify the expression of l ymphocyte D3 receptor mRNA. 3. These results indicate short-lasting dynamic changes of expression of ly mphocyte DIB dopamine receptor mRNA by haloperidol and suggest that the eff ects of dopamine and dopaminergic drugs on the immune system might be media ted, at least in part, by direct interaction of these substances with dopam ine receptors on lymphocyte membrane.