大鼠海马CA3区神经元突触的老龄性改变

Changes of synapse in hippocampus CA3 neurons in aged rats

目的 :观察老龄大鼠海马CA3区神经元突触超微结构的改变 ,探讨老龄动物海马学习记忆功能减退的形态学基础。方法 :应用透射电镜技术 ,观察青年组 (3～ 5月龄 )和老龄组 (2 4～ 2 6月龄 )Wistar大鼠海马神经元的超微结构。结果 :老龄组海马CA3区神经元的主要变化 :突触连接缩短或间断、突触前后膜融合 ;突触小胞大量集聚、小胞大小不等 ;树突棘内棘器远离突触后膜 ,其扁平小囊增多并扩张。结论 :老龄大鼠海马CA3区神经元突触发生了明显的变性改变 ,这可能是导致学习记忆障碍的形态学基础。

Objective: To observe the synapse changes of the neurons in hippocampus CA3 of aged rat and to provide the morphological basis for the mechanism of learning and memory in aged rats. Methods: The synaptic changes of hippocampus neurons in young rats ( 3 to 5 months old) and in aged rats (24 to 26 months old) were observed with electron microscopy. Results: The synaptic connection in aged rats were shortening or discontinuing; fusion of presynaptic and postsynaptic membranes could be observed. The synaptic vesicles in aged rats increased, the size were different, and accumulation presented. The spine apparatus were far away from postsynaptic membrane; the flat vesicles of the spine apparatus were expanding and increased in number. Conclusion: The neurons and synapses of hippocampus CA3 in aged rats presented degenerative changes. The results provided morphological basis for decreasing of learning and memory functions in aged rats.