尼古丁对小鼠空间学习记忆能力的影响

Effect of nicotine on spatial learning and memory of mice

目的研究尼古丁对小鼠空间学习记忆能力的影响。方法 20只雄性14周龄小鼠被随机分为尼古丁组和对照组,尼古丁组9只,对照组7只,其余4只经筛选后剔除。尼古丁组每天腹腔注射尼古丁溶液250 nmol.kg-1连续13 d;对照组腹腔注射等容积的纯水。用Morris水迷宫测小鼠的空间学习记忆能力;小鼠寻找水下平台的时间作为评价学习记忆功能的指标。结果定位航行实验第2天、第3天尼古丁组潜伏期比对照组长,差异有统计学意义(P<0.05);其余各时间点2组潜伏期比较差异无统计学意义(P>0.05)。尼古丁组小鼠在SE象限的游泳时间为(111.89±21.53)s,高于对照组的(85.44±12.56)s,差异有统计学意义(P<0.05)。反向学习第4天尼古丁组小鼠的潜伏期长于对照组,差异有统计学意义(P<0.05);其余各时间点2组潜伏期比较差异无统计学意义(P>0.05)。结论尼古丁短期内能够降低小鼠空间学习能力,长期应用后其效应变弱。

Objective To study the effect of nicotine on spatial learning and memory of mice. Methods A total of 20 male 14-week-old mice were randomly divided into nicotine group（ n = 9 ） and control group（ n = 7 ）, another four mice were excluded. The mice in nicotine group were injected with nicotine at a dose of 250 nmol · kg-1 per day for thirteen days. The mice in control group were injected with similar volume of water. Morris water maze was used to assess the spatial learning and memory of mice. The time of mice spend to find the hidden platform under the surface of water was used to evaluate the ability of learning and memory of mice. Results The latency on the 2＂d and 3＇h day in the nicotine group was significantly longer than that in the control group in place navigation experiment （P 〈 0.05 ） ;there was no significant difference at other time point be- tween the two groups（ P 〉 0. 05 ）. The swimming time of mice in the SE quadrant of nicotine group was （ 111.89 ± 21.53 ） s, and in control group was（ 85.44 ± 12.56）s, the difference was statistic significance（ P 〈 0.05 ）. The latency of nicotine group was significantly longer than that in the control group on the 4th day of the reverse learning （ P 〈 0.05 ） and no significant difference was found at another time point （ P 〉 0.05 ）. Conclusion The nicotine can reduce the spatial learning ability of mice within a few days. However,the effect of nicotine seems to decrease in a long period of time.