异氟醚对东莨菪碱致空间认知障碍大鼠胆碱能毒蕈碱受体活性的影响

Effects of Isoflurane on Choline Acetyltransferase Activity and Binding Capacity of Muscarinic Receptors in S copolamine-treated Rat Brain

目的观察异氟醚对东莨菪碱致空间认知障碍大鼠脑皮层和海马组织中胆碱能毒蕈碱受体(M-R)活性的影响。方法雄性SD大鼠56只随机分为8组:对照/1d组,异氟醚/1d组,东莨菪碱/1d组,异氟醚+东莨菪碱/1d组;对照/7d组,异氟醚/7d组,东莨菪碱/7d组,异氟醚+东莨菪碱/7d组。异氟醚组、异氟醚+东莨菪碱组大鼠每天吸入1MAC(1.5%)异氟醚2h,连续4d。在末次给药后1d,对东莨菪碱/1d组、异氟醚+东莨菪碱/1d组大鼠腹腔注射东莨菪碱0.8mg/kg,连续3d;在末次给药后7d,对东莨菪碱/7d组、异氟醚+东莨菪碱/7d组大鼠给予相同处理。给药完毕后急性断头处死大鼠,分离脑皮层和海马,放射配体结合分析法测定M-R的活性。结果与对照/1d组和异氟醚/1d组相比,东莨菪碱/1d组、异氟醚+东莨菪碱/1d组海马M-R活性降低(P<0.01)。与对照/1d组相比,异氟醚/1d组海马M-R活性增高(P<0.05)。与东莨菪碱/1d组相比,异氟醚+东莨菪碱/1d组海马M-R活性增高(P<0.01)。与对照/7d组和异氟醚/7d组相比,东莨菪碱/7d组、异氟醚+东莨菪碱/7d组海马M-R活性降低(P<0.05)。结论大鼠持续吸入1.5%异氟醚4d(每天2h)可增加海马M-R的活性。

Objective To investigate the effects of isoflurane on binding capacity of muscarinic in the scopolamine-treated rat brain. Methods Fifty-six healthy male SD rats were randomly divided into 4 groups ： （A） control group （n= 14） ; （B） isoflurane group （Iso, n= 14） ; （C） scopolamine group （Sco, n =14） and （D）Iso ＋Sco group （n=14）. Each group was further divided into 2 subgroups - 1 d and 7 d. In Iso （B） and Iso＋Sco （D） groups the animals received 1.5% isoflurane （1 MAC） inhalation 2 h a day for 4 days; while in control （A） and Sco （C） groups the animals had nothing by mouth at the same time. Starting from the 1st day （1 d subgroup） or 7 th day （7 d subgroup） after isoflurane inhalation or 2h no food and water, scopolamine 0. 8mg/kg was given intraperitoneally everyday for 3 days in Sco （C） and Iso＋Sco （D） groups; whereas in control （A） and Iso （B） groups intrperitoneal normal saline was given instead of scopolamine. Then the rats were decapitated and cerebral cortex and hippocampus were removed. The binding capacity of muscarinic receptor was determined. Results The binding capacity of M-R in hippocampus was significantly higher in control group （A） and Iso group （B） than in Sco group （C） and Iso＋Sco group （D） including both 1 d and 7 d subgroups. Among the 4 1-d subgroups the binding capacity of M-R in hippocampus was significantly higher in group B than group A and higher in group D than group C. Conclusion Isoflurane inhalation can change muscarinic receptor in hippocampus.