Involvement of dopamine D1 and D2 receptors in the nucleus accumbens core and shell in inhibitory response control

Rationale Impaired inhibitory control over behavior is a key feature in various psychiatric disorders, and recent studies indicated an important role for dopamine D₁ and D₂ receptors and the nucleus accumbens (Acb) in this respect. Objective The present experiments were designed to study the role of dopamine D₁ and D₂ receptors in the Acb in inhibitory response control. Methods Rats were trained in a five-choice serial reaction time task and received bilateral infusions into the Acb core or shell of either SCH 23390 or eticlopride (representing selective dopamine D₁ and D₂ receptor antagonists, respectively). Subsequently, the effects of systemic amphetamine on inhibitory response control were examined. Results Eticlopride into either the Acb core or shell did not affect premature responding, a measure for inhibitory response control, but increased reaction time and errors of omission. In contrast, SCH 23390 into both regions reduced premature responding, slightly improved attentional performance in the core and increased errors of omission in the shell. Amphetamine robustly increased premature responding which was dose-dependently blocked by eticlopride in the Acb core and attenuated by eticlopride in the shell. In addition, amphetamine slightly decreased accuracy and reaction time, and these effects were inhibited by eticlopride in both regions. SCH 23390 infusion into the Acb core or shell did not alter amphetamine’s effects. Conclusion Our data provide evidence for the involvement of dopamine D₁ and D₂ receptors in the Acb core and shell in inhibitory response control and attentional performance.