大鼠海马结构及其CCK神经元在学习记忆中的作用研究

目的通过毁损海马结构不同区域造成学习记忆减退模型,探讨海马结构及神经递质CCK神经元在学习记忆中的作用。方法SD大鼠48只,随机分成4组1双侧海马穹窿伞横断组;2海马CA3区锥体细胞KA损毁组;3实验对照组;4正常对照组。以大鼠被动回避反应和Morris水迷宫试验为指标测定实验动物学习记忆能力,采用免疫组织化学技术观察海马结构CCK神经元的变化。结果经两种方式毁损海马结构不同区域干扰海马传导通路后,大鼠学习记忆能力明显障碍。且经1~4W观察,学习记忆功能无明显恢复。在双侧隔海马伞横断组和海马CA3区锥体细胞KA损毁组均伴有CCK神经元质和量的改变,但以海马CA3区锥体细胞KA损毁组尤为突出,除表现为数量减少外,细胞的损伤性改变较双侧隔海马伞横断组明显。结论海马CA3区注入海人酸后引起的学习记忆障碍程度较海马穹窿伞横断所引起的严重。海马CA3区KA注射后除引起CCK神经元数量减少外,尚伴有CCK神经元的损伤,而双侧海马穹窿伞横断后CCK神经元改变主要是数量减少,神经元损伤不明显。海马功能的完整不仅依赖于结构的完整,同时也依赖于各种神经递质的参与和神经递质质和量的正常。

Studies on the influence of hippocampal formation and CCK neurons on learning and memory in rats

Objective: To evaluate the influence of hippocampus formation and CCK neurons on learning and memory. Methods: In this study, interruption of the intrinsic and extrinsic connections of the hippocampus was made by two means:①the fornix-fimbria of hippocampus was transected;②the CA3 pyramidal cell layer was destroyed by microinjection of KA. Rats in which the various areas of the hippocampus was destroyed by surgery were tested by behavioral measures . Two behavioral measures were the passive avoidance test and the morris water maze test. Sections were stained with ACh Eenzymatic cytochemical technique and CCK immunohistochemical technique to observe their changes. Results: The learning and memory of the rats injected with KA was more difficult than other groups. The CCK neurons had changed in quality and quantity. These changes demonstrated that the damage of some CCK neurons after KA injection were so obvious.The changes which mainly involved CA1 and CA3 were the lesion of CA3 pyramidal cell-induced by microinfusion of KA. Conclusion: Our experiments, combined with results reported previously, demonstrate that hippocampus may play the key role in learning and memory function. The CCK neurons in the hippocampus enhance learning and memory function.