慢性应激大鼠海马 DG 区牛磺酸在空间学习记忆过程中的变化

摘要

目的：观察海马齿状回（Dentate Gyrus，DG）区的牛磺酸（Taurine，Tau）在慢性应激模型大鼠空间学习记忆过程中的变化，初步探讨慢性应激影响大鼠空间学习记忆能力的部分机制。方法SD 雄性大鼠16只，随机分为对照组和慢性应激组。以多种刺激随机应用的方法制备慢性应激大鼠模型，并利用脑部微量透析法和 HPLC 法实时观察慢性应激大鼠海马 DG 区细胞外液中 Tau 的含量。其次，利用 Morris 水迷宫（Morris Water Maze，MWM）观察大鼠的空间学习记忆能力，并观察海马 DG 区 Tau 含量在 MWM 训练过程中的变化。结果1）慢性应激组大鼠海马 DG区细胞外液中的 Tau 含量明显高于对照组（P ＜0．05）。2）MWM 的定位航行实验中，两组大鼠的逃避潜伏期均随着训练次数的增加而减少，而慢性应激组大鼠训练第4天的逃避潜伏期明显小于对照组（P ＜0．05）；MWM 的空间探索实验中，慢性应激组的穿越原站台区次数显著多于对照组（P ＜0．05）。3）MWM 训练过程中，慢性应激组大鼠海马DG 区的 Tau 含量出现明显的增加（P ＜0．05），而对照组大鼠海马 DG 区的 Tau 含量未出现明显变化（P ＞0．05），两组间有显著性差异（P ＜0．05）。结论慢性应激可以提高大鼠的空间学习记忆能力，这可能与海马 DG 区的 Tau 含量增加有关。%Objective To observe the changes of extracellular level of taurine (Tau)in the hippocampal dentate gy-rus (DG)in a rat model of chronic stress during Morris water maze (MWM)test,and primarily investigate the neuro-chemical mechanism responsible for effect of chronic stress on spatial learning and memory.Methods Totally 16 SD rats were randomly divided into two groups,control group and chronic stress (CS)group.The rat model of CS was pre-pared by random application of varied stressors,and then the extracellular concentration of Tau in the DG was deter-mined by in vivo microdialysis and HPLC.Next,the spatial learning and memory abilities of rats were assessed by Mor-ris water maze (MWM),and the extracellular concentration of Tau in the DG was simultaneously observed.Results 1) Compared with the control group,the extracellular concentration of Tau in hippocampal DG was significantly increased in CS group (P <0.05).2)In the place navigation trial of MWM test,the escape latency decreased in both control and CS groups over the course of the training days,however,on the 4th day,escape latency was significantly shorter in CS group compared with control group (P <0.05);in the spatial prove trial of MWM test,the number of platform cross-ings was markedly increased in CS group compared with control group(P <0.05).3)During MWM test,Tau level in the DG was significantly increased in CS group (P <0.05),while it was not changed in control group(P >0.05).Con-clusion Chronic stress facilitates the spatial learning and memory in rats,which may be related to the increase of Tau in hippocampal DG region.