七氟烷对老年大鼠海马毒蕈碱受体M,表达和认知功能的影响

目的 探讨不同剂量七氟烷对老年大鼠海马毒蕈碱受体M.受体亚型(mAChR M1)表达的影响及与认知功能的关系.方法 40只SD大鼠随机分为空白对照组(Con组)、1.5%七氟烷Ⅰ组(1.5%Sev Ⅰ组)、1.5%七氟烷Ⅱ组(1.5%Sev Ⅱ组)、3.0%七氟烷sev Ⅰ组(3.O%Sev Ⅰ组)和3.0%七氟烷Ⅱ组(3.0%SevⅡ组),每组8只.Con组吸入空气2h,1.5%Sev Ⅰ组、1.5%Sev Ⅱ组、3.0%Sev Ⅰ组和3.0%SevⅡ组分别吸入1.5%或者3.0%七氟烷2h.于给药后1 d或7d采用Y型迷宫实验测试学习记忆能力后即刻处死取脑,分离海马,通过RT-PCR法检测mRChR M1 mRNA表达,免疫组化法检测海马神经细胞M1受体的表达.结果 3.0%sev Ⅰ组学习次数,训练时间[分别为(41.83±4.30)次,(48.76±1.24)min]高于对照组[分别为(33.50±4.80)次,(38.24±0.68)min],差异有显著性(P<0.05),海马mAChR M1(42.12±0.66)和mAChR M1mRNA表达低于对照组mAChR M1(70.21±0.45)和mAChR M1 mRNA表达水平,差异有显著性(P<0.05).结论 七氟烷麻醉时,可以引起老年大鼠学习记忆能力一过性降低,可能与大鼠海马mAChR M1下调有关.

Effect of sevoflurone on the expression of M1 acetylcholine receptor in the hippocampus and cognitive of aged rats

Objective To investigate the effect of 1.5% and 3.0% sevoflurone on the expression of M1 acetylcholine receptor( mRChR M1 ) in the hippocampus and the cognition of aged rats. Methods Forty SD rats weighting 560～600g were randomly divided into 5 groups (n=8): Con group, 1.5% Sev Ⅰ group, 1.5% Sev Ⅱ group,3.0% Sev Ⅰ group and 3.0% Sev group. Each group of rats were anesthetized 2 h by 1.5% sevoflurone (1.5%Sev Ⅰ group and 1.5% Sev Ⅱ group) 3.0% sevoflurone (3.0% Sev Ⅰ group and 3.0% Sev group ) or false anesthetized 2 h by air(Con group). Y-maze was used to test the ability of learning and memory half of each group of rats after 1 d and 7d. Then rats were decapitated,and removed the hippocampus. The relative expression level of mAChR M1 mRNA in the hippocampus of rats were tested by RT-PCR,and the expression of mAChR M1 were test-ed by immunohistochemistry. Results The numbers and times of study[respectively(41.83±4.30), (48.76±1.24)min] in 3.0% Ⅰ Sev group were increased compared with that in the Con group[respectively(41.83±4.30 ), (48.76±1.24) min] after the rats be anesthetized 1 d (P<0.05). 3.0% Ⅰ Sev group hippocampal M1 re-ceptor(42.12±0.66) and mAChR M1 mRNA expression level reduced compared with that in the Con group after be administrated 1 d (P<0.05 ). There was no significant difference in the numbers and times of study and M1 receptor expression level in the other groups. Conclusion The ability to learn and memory can be reduced for a short time after sevoflurane inhalation through down-regulation of mAchR M1 in the brain.