远志对阿尔茨海默病模型大鼠学习记忆及在体海马LTP的影响

目的观察远志对阿尔茨海默病(Alzheimer’s disease,AD)模型大鼠学习记忆能力及在体海马突触传递长时程增强(long-term potentiation,LTP)的影响,探讨该中药对AD的作用及其电生理机制。方法将32只雄性Wistar大鼠随机分为正常组、模型组、远志低剂量组、远志高剂量组。模型组在D-半乳糖致衰老基础上定向注射鹅膏蕈氨酸,行Meynert基底核损毁建立AD大鼠模型;远志高、低剂量治疗组则在造模的同时用远志水煎剂灌胃;后用水迷宫实验对动物学习记忆能力进行评价,并用电生理学方法通过对高频刺激前后海马CA1区场兴奋性突触后电位(field exciatatory postsynaptic potential,fEPSP)幅度的比较检测大鼠海马LTP的变化。结果模型组大鼠的学习记忆能力、兴奋性突触后电位与正常组相比明显下降(P0.01);远志高、低剂量组大鼠的学习记忆能力、兴奋性突触后电位与模型组相比均明显提高(P0.01或P0.05);远志低剂量组大鼠的学习记忆能力、兴奋性突触后电位较远志高剂量组明显降低(P0.01)。结论远志可提高AD模型大鼠的学习记忆能力,并对AD模型大鼠在体海马LTP具有促进作用,且上述作用具有剂量依赖性。

In Vivo Effects of Radix Polygalae on Learning, Memory and the Hippocampal Long-Term Potentiation in AD Model Rats

Objective To observe the in vivo impacts of radix polygalae on learning,memory and the hippocampal long-term potentiation（LTP）in rats with Alzheimer＇s disease（AD）,and discuss the function of Chinese herbal medicine for AD as well as its electrophysiological mechanism.Methods 32 male Wistar rats were divided randomly into normal group,model group,control group,low-dose radix polygalae group and high-dose radix polygalae group.In model group,AD rat model was established by oriental injection of ibotenic acid（IA）on the basis of aging induced by D-gatactose,resulting in the damage of basal nucleus of Meynert.In low-dose and high-dose radix polygalae groups,while modeled,the decoction of radix polygalae was used for gastric infusion.Afterwards,water maze test was performed to assess the ability of learning and memory of animals.Additionally,electrophysiological technique was used to observe the changes in rat hippocampal LTP through the comparison of field excitatory postsynaptic potential（fEPSP）amplitudes in hippocampal CA1 region before and after high frequency stimulation（HFS）.Results Compared with control group,the ability of learning and memory as well as fEPSP obviously descended in model group（P0.01）.Those in either high-dose or low-dose radix polygalae group were enhanced significantly compared with the model group（P0.05,P0.01）.Compared with the high dose radix polygalae group,the ability of learning and memory and fEPSP obviously decreased in low dose radix polygalae group（P0.01）.Conclusion Radix polygalae can significantly improve the ability of learning and memory and promote in vivo hippocampal LTP.Additionally,the dose-dependence presents in the above effects.