老年学习记忆减退大鼠的海马GABA能神经元数量变化

Change of GABAergic Neurons in Hippocampus of Aged Learning and Memory Impaired Rats

为探讨γ-氨基丁酸 (GABA)能神经元在老年脑的改变及其与老年性学习记忆减退间的关系。本研究通过 Morris水迷宫测试将老年大鼠分为学习记忆正常和损害组 ,用免疫细胞化学和体现视学方法定量描述 GABA能神经元的改变。结果显示 ,老年记忆正常和损害组海马本部各区的 GABA能神经元均较年轻组明显减少 ,但正常组和损害组海马之间无显著性差异。齿状回分子层的 GABA阳性神经元的数量仅在老年学习记忆损害组明显减少 ,且 GABA神经元数量与搜寻平台的游泳时间呈负相关 (r=- 0 .91,P<0 .0 1)。提示老年学习记忆能力减退可能与齿状回分子层的

The propose of this study was to explore the behavioral features and its relation to GABAergic neurons in the hippocampal formation of the aged rat. 40 aged SD rats (24 months) were divided into agedimpaired group and aged-unimpaired group according to the swim time of platform trial performance in the Morris water maze. 15 young rats (3 months) were used as control. The changes of GABAergic neurons in the hippocampus of the rats were estimated by immunocytochemical and stereological methos. The results showed that the average area densities (N A) of GABAergic neurons in subiculum, field CA1, field CA3, and field CA4 decreased in aged rats compared to the young rats, but no significant differences in the two aged groups. In the dentate gyrus, decrease of GABAergic neurons occurred only in aged impaired rats. Correlative analysis showed that the N A of GABAergic neurons in the molecular layer of dentate gyrus had a negative correlation with the mean escape latency in place discrimination learning (γ= 0.91, P<0.01). The results suggest that the loss of GABAergic neurons in the molecular layer of dentste gyrus is an important cause for the decline of learning and memory in the aged rat.