Dopamine D(1) receptor stimulation modulates the formation and retrieval of novel object recognition memory: Role of the prelimbic cortex

Previous studies have shown that dopamine D(1) receptor antagonists impair novel object recognition memory but the effects of dopamine D(1) receptor stimulation remain to be determined. This study investigated the effects of the selective dopamine D(1) receptor agonist SKF81297 on acquisition and retrieval in the novel object recognition task in male Wistar rats. SKF81297 (0.4 and 0.8 mg/kg s.c.) given 15 min before the sampling phase impaired novel object recognition evaluated 10 min or 24 h later. The same treatments also reduced novel object recognition memory tested 24 h after the sampling phase and when given 15 min before the choice session. These data indicate that D(1) receptor stimulation modulates both the encoding and retrieval of object recognition memory. Microinfusion of SKF81297 (0.025 or 0.05 μg/side) into the prelimbic sub-region of the medial prefrontal cortex (mPFC) in this case 10 min before the sampling phase also impaired novel object recognition memory, suggesting that the mPFC is one important site mediating the effects of D(1) receptor stimulation on visual recognition memory.