Cocaine induced T cell proliferation in the rat: role of amygdala dopamine D1 receptors.

The immunomodulatory effects of local administration of cocaine into the amygdala were studied in the rat. Intra-amygdala infusion of cocaine significantly and dose-dependently increased the proliferative response of splenocytes to concanavalin A (Con A). A similar effect on the immune response was also observed in rats, microinfused into the central amygdala with the selective D1 receptor agonist SKF 38393. The increase of the proliferative response of splenocytes to Con A was inhibited by coinfusion within the central amygdala of the dopamine D1 receptor antagonist SCH 23390, together with cocaine, but not by coinfusion of the dopamine D2 receptor antagonist eticlopride. These results suggest that cocaine may produce at least some of its effects on the immune system through the activation of brain dopamine neurotransmission and that the central amygdala may represent a critical structure mediating cocaine-induced T cell proliferation.