There is evidence that psychostimulant drugs can influence the immune response. We previously demonstrated that a single exposure to amphetamine (AMPH) decreases the lymphoproliferative response in rats, and that dopaminergic antagonist pretreatments can suppress this AMPH?s effect. The main goal of this work was to study the participation of central dopaminergic system in this effect by a selective destruction of mesolimbic dopamine (DA)-containing terminals produced by bilateral injection of 2 mg of 6-hydroxy-DA (6OHDA) into the nucleus accumbens of Wistar rats pretreated with desipramine. Two weeks following the lesion, the animals received an acute AMPH dose (5mg/kg IP) and the proliferative response was assessed 4 days after. In 6OHDA pretreated rats we obtained a reduction of DA levels of a 51.4% (+/- 4.6) related to control. AMPH caused a decrease (73% +/- 8) in the concanavalin-A-induced lymphocyte proliferation that was completely abrogated in 6OHDA pretrated animals. Our results clearly indicate that mesolimbic DA is primarily involved in the AMPH?s effect on lymphoproliferative response.
