Enhanced and impaired attentional performance after infusion of D1 dopaminergic receptor agents into rat prefrontal cortex

The role in spatial divided and sustained attention of D1 and D2-like dopam ine (DA) receptors in the rat prelimbic medial prefrontal cortex (mPFC) was investigated in a five-choice serial reaction time task. Rats were trained to detect brief flashes of light (0.5-0.25 sec) presented randomly in a sp atial array of five apertures. When performance stabilized, animals receive d bilateral microinfusions of either the D1 DA receptor antagonist SCH 2339 0, the D1 DA receptor agonist SKF 38393, or the D2 DA antagonist sulpiride into the mPFC. Rats were divided into two groups, with low (<75% correct) a nd high (>75%) baseline levels of accuracy. Infusions of the D2 receptor an tagonist sulpiride had no significant effect on any task variable. SCH 2339 0 (0.3 mu g) selectively impaired the accuracy of attentional performance i n rats in the high baseline condition. By contrast, SKF 38393 (0.06 mu g) e nhanced the accuracy of attentional performance in the low baseline conditi on, a lower dose (0.03 mu g) also increasing the speed of making correct re sponses. Finally, the beneficial effects of SKF-383893 on choice accuracy w ere antagonized by SCH 23390 (1.0 mu g). The results provide apparently the first demonstration of enhanced cognitiv e function after local administration of a D1 receptor agonist to the mPFC and suggest dissociable roles of D1 and D2 DA receptors of the mPFC in modu lating attentional function.