Effects of nicotine on spatial learning in C57BL mice

In the present study, the effects of nicotine on spatial memory in C57BL/6J mice was evaluated. Mice were trained in a water maze during four daily sessions of three trials each. In the first experiment, nicotine (0.7 and 0.35 mg/kg) or saline was administered once daily for 4 days, 15 min before the start of daily training: an impairment of performance of the water maze was observed in the group treated with 0.7 mg/kg of nicotine. In the second experiment, nicotine (0.7 and 0.35 mg/kg) or saline was administered from the 5 days prior to the beginning of the task and during the 4 days of acquisition. The results indicated an improvement in the rate of learning in the 9-day nicotine treated groups. The comparison between 4-day and 9-day treated groups revealed that the group receiving 0.35 mg/kg of nicotine for 9 days displayed significantly shorter latencies than all the other groups, while the group receiving 0.7 mg/kg of nicotine for 4 days performed significantly worse than all the other groups. The most noteworthy result is that nicotine was more effective after a more prolonged administration than when administered only during the training days. (C) 1999 Lippincott Williams & Wilkins.