Modafinil reduces choice impulsivity while increasing motor activity in preadolescent rats treated prenatally with alcohol

Abstract

Rats exposed prenatally to alcohol show a reduction in the spontaneous activity of dopaminergic neurons of the ventral tegmental area (VTA), as well as greater impulsive behavior and motor activity, behavioral alterations that have been related to dopaminergic dysfunction. Modafinil (MOD) is a dopamine (DA) reuptake blocker prescribed to treat sleep disorders; however, in recent years it has been used for the treatment of ADHD with positive results. Also, studies in humans and rodents show beneficial effects on learning and attention; however, studies evaluating MOD effects on impulsivity are few and show contradictory results. The purpose of this work was to evaluate the effect of a daily dose of MOD (60 mg/kg i.g.) on cognitive (or choice) impulsivity and motor activity in male preadolescent rats exposed prenatally to alcohol or sucrose (isocaloric control). MOD reduced the impulsive responses in a delay discounting task (DDT) at the same time that increased the motor activity, in both healthy and prenatal alcohol treated rats; however, MOD reduced the response latency in DDT only in prenatal alcohol treated rats. This differential effect of DA activation on impulsivity and motor activity show that the MOD dose that improves the impulse control, does not necessarily decrease motor activity, and suggests a possible differential neural mechanism underlying the expression of these behaviors. On the other hand, the changes in the response latency, only in prenatal alcohol treated groups, suggest that decision-making in animals with a dopaminergic dysfunction is more susceptible to be affected by MOD action.