We determined the effect of nefiracetam, a novel cognitive enhancer, on the extracellular acetylcholine (ACh) level in the frontal cortex of freely moving rats, using a microdialysis technique without an acetylcholinesterase inhibitor in the perfusate. Treatment with nefiracetam (10 mg/kg, p.o.) produced a significant increase in the level of ACh in the brain dialysate, compared with the vehicle-treated group. This enhancing effect was also observed when the ACh level was elevated by administration of scopolamine (1 mg/kg, i.p.) at 45 min after the treatment with nefiracetam. In addition, perfusion of nefiracetam at the concentration of 10 microM significantly increased the extracellular ACh level in the frontal cortex of basal forebrain (BF)-lesioned rats, in which a marked decrease of the basal ACh level was observed in this region. These results suggest that enhancement of cortical ACh release by nefiracetam may contribute to an anti-amnesic effect on the learning deficits induced by treatment of scopolamine or BF-lesion in rats.