Prenatal cocaine exposure increases sensitivity to the attentional effectsof the dopamine D1 agonist SKF81297

Sensitivity to the attentional effects of SKF81297, a selective full agonis t at dopamine D-1 receptors, was assessed in adult rats exposed to cocaine prenatally (via intravenous injections) and controls. The task assessed the ability of the subjects to monitor an unpredictable light cue of either 30 0 or 700 msec duration and to maintain performance when presented with olfa ctory distractors. SKF81297 decreased nose pokes before cue presentation an d increased latencies and response biases (the tendency to respond to the s ame port used on the previous trial), suggesting an effect of SKF81297 on t he dopamine (DA) systems responsible for response initiation and selection. The cocaine-exposed (COC) and control animals did not differ in sensitivit y to the effects of SKF81297 on these measures. In contrast, the COC animal s were significantly more sensitive than were controls to the impairing eff ect of SKF81297 on omission errors, a measure of sustained attention. This pattern of results provides evidence that prenatal cocaine exposure produce s lasting changes in the DA system(s) subserving sustained attention but do es not alter the DA system(s) underlying response selection and initiation. These findings also provide support for the role of D1 receptor activation in attentional functioning.