Resumo

Aims: Dopamine (DA) and N-methyl-D-aspartate (NMDA) receptors modulate cognitive functions in the prefrontal cortex (PFC) and the effects of alcohol in the central nervous system. This study examined the involvement of DA and NMDA receptors of the medial PFC (mPFC) in the disruptive effects of ethanol on a delayed task in rats. Methods: Adult male Wistar rats, well trained in 8-arm radial maze procedures and bilaterally cannulated in the mPFC, received intracortical (IC) administrations of SCH-23390 (1.0 µg) or saline (SAL) followed, 10 min later, by different doses of ethanol (SAL, 32, 100, 180 µg), and were tested in 1 h delayed tasks in the radial maze. Different animals received IC administrations of sulpiride (0.32, 3.2 µg) or vehicle (HCl 0.05 M), clozapine (0.32, 3.2 µg) or vehicle, MK-801 (0.32, 3.2 µg) or SAL, memantine (1.0, 10.0 µg) or SAL, followed 10 min later by 100 µg ethanol, and were tested in 1 h delayed tasks. . Results: 100 µg ethanol significantly increased the number of errors after the 1 h delay interposition as compared to the control (p < 0.01). This disruptive effect of 100 µg ethanol on 1 h delayed task was significantly reduced by SCH-23390 (1.0 µg)(p < 0.01), clozapine (3.2 µg) (p < 0.05) or memantine (10.0 µg) (p < 0.05) administered previously into the mPFC. Conclusions: These results showed that the disruptive effects of ethanol were significantly reduced by previous intracortical administration of SCH-23390, clozapine or memantine, suggesting that DA and NMDA receptors may be involved in the effects of ethanol on prefrontal functions.