毒扁豆碱对抗吗啡诱导大鼠空间回忆障碍的作用

Effect of physostigmine on morphine-induced spatial recall impairment in rats

目的:运用Morris水迷宫任务分析吗啡及其与胆碱能系统的相互作用对大鼠回忆空间任务的影响。方法:实验于2004-09在首都师范大学“北京市重点实验室-学习与认知实验室”完成。实验动物为5月龄雄性Wistar大鼠36只,体质量180～210g。使用Morris水迷宫训练大鼠在20s内找到隐蔽站台。训练结束后的第1天,动物随机分为6组,1个对照组和5个实验组。每组6只,测试回忆能力。在第2天和第9天,动物分组同时接受两次腹腔注射:第1组(对照组),注射生理盐水和生理盐水;第2组,注射吗啡(10mg/kg)和生理盐水;第3组,注射毒扁豆碱(0.1mg/kg)和生理盐水;第4组,注射吗啡(10mg/kg)和毒扁豆碱(0.1mg/kg);第5组,注射吗啡(10mg/kg)和毒扁豆碱(0.2mg/kg);第6组,注射吗啡(10mg/kg)和纳洛酮(0.5mg/kg)。注射药物后30min,测试动物在水迷宫中找到隐蔽站台的潜伏期。结果:在实验过程中,无动物死亡,全部进入结果分析。①实验期给药之前的第1天,各组大鼠找到站台的潜伏期在各组间差异无显著性。②实验期第2天和第9天,第2组(注射吗啡)的大鼠找到站台的潜伏期与对照组比较显著延长,差异有显著性[(87±22.527),(16.167±3.736)s,P<0.001];[(96.667±20.851),(16.333±2.361)s,P<0.001]。③实验期第2天和第9天,第3组(注射毒扁豆碱0.1mg/kg)大鼠找到站台的潜伏期与对照组比较差异无显著性(均为P>0.05)。第4组(同时注射吗啡和毒扁豆碱0.1mg/kg)与对照组相比,大鼠找到站台的潜伏期延长(均为P<0.01);与第2组相比,潜伏期略微缩短,但无统计学意义(均为P>0.05)。第5组(注射吗啡和毒扁豆碱0.2mg/kg)的大鼠找到站台的潜伏期与对照组比较无明显改变;但与第2组(注射吗啡)比较,潜伏期显著缩短,差异有显著性[第2天,(26±5.790),(16.333±2.361)s,P<0.01];[第9天,(31.667±7.337),(16.333±2.361)s,P<0.001]。④实验期第2天和第9天,第6组(同时注射吗啡10mg/kg和纳洛酮0.5mg/kg),分别与对照组及第5组比较,大鼠找到站台的潜伏期均没有明显变化(均为P>0.05);与第2组比较,潜伏期则显著缩短,差异有显著性[第2天,(34.667±6.746),(87±22.527)s,P<0.01];[第9天,(22.167±6.457),(96.667±20.851)s,P<0.001]。结论:吗啡(10mg/kg)能够抑制大鼠对水迷宫任务的回忆;这种抑制作用可能与吗啡抑制中枢胆碱能递质系统功能有关,毒扁豆碱通过加强胆碱能递质系统的活动,从而对抗吗啡诱导的空间回忆障碍。

AIM： To analyze the effect of morphine and its interaction with cholinergic system on the spatial recall process of rats by Morris water maze performance. METHODS： The experiment was carried out in the Beijing Key Laboratory （Learning and Cognition Laboratory） of Capital Normal University in September 2004, The experimental animals were thirty-six Wistar rats of 5 months weighing 180-210 g. Morris water maze was used to train all the rats to find the covert platform in it within 20 seconds. On the 1^st day after the end of training, the rats were randomly divided into six groups in each group with 6 rats in each group： one control group and 5 experimental groups, the recall ability was tested. On the 2^nd and 9^th days, the animals received intraperitoneal injection for twice while grouping： rats in Group 1 （control group） were injected with saline and saline, Group 2 received 10 mg/kg morphine and saline, Group 3 received 0.1 mg/kg physostigmine and saline, Group 4 received 10 mg/kg morphine and 0d mg/kg physostigmine, group 5 received 10 mg/kg morphine and 0.2 mg/kg physostigmine, Group 6 received 10 mg/kg morphine and 0.5 mg/kg naloxone, The latencies of rats with drugs treatment to find the covert platform were measured at 30 minutes after injections. RESULTS： No animal died during the experiment, and all were involved in the analysis of results. ①On the 1^st day before drug treatment during the experiment, the latencies for the rats to find the covert platform had no significant differences among the groups, ② On the 2^nd and 9^th days during the experiment, the latencies for the rats to find the covert platform in Group 2 （injected with morphine） were significantly prolonged as compared with those in the control group [（87±22.527）, （16.167±3.736） s, P 〈 0.001; （96.667±20.851）, （16.333±2.361） s, P 〈 0.001]. ③ On the 2^nd and 9^th days during the experiment, the latencies for the rats to find the covert platform in Group 3 （injected with 0.1 mg/kg physostigmine） were not significantly different from those in the control group （P 〉 0.05）; The latencies in Group 4 （injected with morphine and 0.1 mg/kg physostigmine） were prolonged as compared with those in the control group （P 〈 0.01）, but slightly shortened but insignificantly as compared with those in Group 2 （P 〉 0.05）, The latencies in Group 5 （injected with morphine and 0.2 mg/kg physostigmine） had no obvious change as comoapred with those in the control group （P 〉 0.05）, but significantly shortened as comarped with those in Group 2 （injected with morphine） [on the 2^nd day （26±5.790）, （16.333±2.361） s, P 〈 0.01; on the 9^th day： （31.667±7.337）, （16.333±2.361） s, P 〈 0.001].④ On the 2^nd and 9^th days during the experiment, the latencies for the rats to find the covert platform in Group 6 （injected with 10 mg/kg morphine and 0.5 mg/kg naloxone） had no obvious changes as compared with those in those in the control group and Group 5 （P 〉 0.05）, hut significantly shortened as compared with those in Group 2 [on the 2^nd day： （34.667±6.746）, （87±22.527） s, P〈 0.01; on the 9^th day： （22.167±6.457）, （96.667±20.851） s, P 〈 0.001]. CONCLUSION： Morphine （10 mg/kg） can evidently inhibit the recall to water maze performance of rats, which may have a close relationship with inhibitory effect of morphine on central cholinergic system. Physostigmine can enhance the activity of cholinergic system, and then antagonizes the morphine-induced spatial recall impairment.