DISTRIBUTION OF GLUTAMATE-LIKE IMMUNOREACTIVITY IN EXCITATORY HIPPOCAMPAL PATHWAYS - A SEMIQUANTITATIVE ELECTRON-MICROSCOPIC STUDY IN RATS
DISTRIBUTION OF GLUTAMATE-LIKE IMMUNOREACTIVITY IN EXCITATORY HIPPOCAMPAL PATHWAYS - A SEMIQUANTITATIVE ELECTRON-MICROSCOPIC STUDY IN RATS
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DOI：
10.1016/0306-4522(90)90277-b
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发表时间：
1990-01-01
期刊：
影响因子：
3.3
通讯作者：
OTTERSEN, OP
中科院分区：
文献类型：
--
作者：
BRAMHAM, CR;TORP, R;OTTERSEN, OP
用半定量电镜免疫细胞化学方法研究了戊二醛固定的谷氨酸在大鼠海马结构的细胞和亚细胞分布。超薄塑料包埋切片与一级谷氨酸抗血清孵育，然后与胶体金颗粒偶联的二级抗体孵育。金颗粒密度的计算机辅助评估显示，在海马中的所有主要兴奋性通路的轴突末梢富含谷氨酸样免疫反应相对于其他组织元素，包括母细胞体（颗粒和锥体细胞）。不同的兴奋性通路显示出略有不同的标记强度：在外侧穿支通路的终止区的终扣被较高的金颗粒密度，位于内侧穿支通路，Schaffer侧支/连合通路和门联合/连合通路的终止区的终扣。苔藓纤维终端显着不丰富的免疫反应性比终端的外侧穿通路径和Schaffer侧支/连合途径。在终端，谷氨酸样免疫反应集中在突触囊泡和线粒体。与细胞体或树突干建立对称连接的终末显示低颗粒密度，胶质细胞过程也是如此。这些发现支持谷氨酸是海马兴奋性突触中主要的兴奋性神经递质的观点。我们的观察结果也与生化数据一致，这些数据表明存在相当大的神经元和较小的神经胶质，谷氨酸代谢池。
A semiquantitative electron microscopic immunocytochemical procedure was used to study the cellular and subcellular distribution of glutaraldehyde-fixed glutamate in rat hippocampal formation. Ultrathin plastic-embedded sections were incubated with a primary glutamate antiserum followed by a secondary antibody coupled to colloidal gold particles. A computer-assisted assessment of gold particle densities revealed that the axon terminals of all of the main excitatory pathways in the hippocampus were enriched with glutamate-like immunoreactivity relative to other tissue elements, including the parent cell bodies (granule and pyramidal cells). The different excitatory pathways showed slightly different labelling intensities: boutons in the termination zone of the lateral perforant path were covered by higher gold particle densities that boutons situated in the termination zones of the medial perforant path, the Schaffer collateral/commissural pathway and the hilar association/commissural pathway. The mossy fibre terminals were significantly less enriched in immunoreactivity than terminals of the lateral perforant path and the Schaffer collateral/commissural pathway. Within the terminals, glutamate-like immunoreactivity was concentrated over synaptic vesicles and mitochondria. Terminals establishing symmetric junctions with cell bodies or dendritic stems displayed low particle densities, as did glial cell processes.These findings support the idea that glutamate is a major excitatory neurotransmitter in hippocampal excitatory synapses. Our observations are also in line with biochemical data pointing to the existence of a considerable neuronal and a smaller glial, metabolic pool of glutamate.