七氟烷和东莨菪碱对老年大鼠海马毒蕈碱受体表达的影响

目的 探讨七氟烷和东莨菪碱对老年大鼠海马毒蕈碱受体表达的影响.方法 健康雄性老年SD大鼠48只,月龄18月,体重560～600 g,随机分为对照组(Con组)、七氟烷组(Sev组)和东莨菪碱组(Sco组),每组16只.Sco组腹腔注射东茛菪碱0.8 mg/kg,Con组和Sev组腹腔注射等容量生理盐水,30 min后Sev组吸入3.0%七氟烷、Con组和Sco组吸入空气2 h.于给药后1、3 d时分别取8只大鼠,采用Y型迷宫实验测试学习记忆能力,然后断头处死,取脑分离海马,采用RT-PCR法检测M1受体和M,受体mRNA的表达,采用免疫组化法检测海马神经元M1受体和M2受体的表达.结果 与Con组相比,给药后1d时Sev组和Sco组学习次数增多、训练时间延长,海马M1受体和M2受体的表达下调(P<0.05);各组间给药后3 d时学习次数、训练时间及海马M1受体和M2受体的表达差异无统计学意义(P>0.05).结论 七氟烷和东莨菪碱均可诱发老年大鼠认知功能一过性降低,其机制与海马M1受体和M2受体表达下调有关.

Efforts of sevoflurane and scopolamine on muscarinic acetylcholine receptors in hippocampus in gerontal rats

Objective To investigate the effects of sevoflurane and scopolamine on muscarinic acetylcholine receptors in hippocampus in gerontal rata.Methods Forty-eight male SD rats aged 18 months weighing 560-600 g were randomly divided into 3 groups(n=16 each):group Ⅰcontrol(C);group Ⅱ inhaled 3%sevoflurane for 2 h(Sevo);group Ⅲ received intraperitoneal scopolamine 0.8 mg/kg.Y-maze was used to test the abihty of learning and memow at 1 and 3 d after drug administration in 8 animals from each group.The animals were decapitated immediately after Y-maze test at 1 and 3 day after drug administration.The hippocampus was removed for determination of the relative levels of expression of M1 and M2 acetylcholine receptor(mAChR M1,M2)mRNA(by RT-PCR)and the expression of mAChR MI and M2(by immuno-histochemistry).Results The ability to learn and remenlber and the expression of M1 and M2 AChR and AChR mRNA were significantly decreased at 1 d after sevoflurane inhalation(in group Ⅱ)and scopolamine IP administration(in group m)aS compared with control group and returned to control level at 3 d.Conclusion The ability to learn and remember cfln be reduced for a short period of time after sevoflurane inhalation and IP scopolamine throgh down-regulation of Ml and M2 mAChR in the brain.