Gap junctions on hippocampal mossy fiber axons demonstrated by thin-section electron microscopy and freeze-fracture replica immunogold labeling
Gap junctions on hippocampal mossy fiber axons demonstrated by thin-section electron microscopy and freeze-fracture replica immunogold labeling
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DOI：
10.1073/pnas.0705281104
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发表时间：
2007-07-24
影响因子：
11.1
通讯作者：
Traub, Roger D.
中科院分区：
文献类型：
--
作者：
Hamzei-Sichani, Farid;Kamasawa, Naomi;Traub, Roger D.
基于电生理学、建模和染料偶联数据，已经假设兴奋性皮层神经元的轴突之间存在间隙连接。在这里，我们提供了超微结构证据的轴-轴间隙连接在齿状颗粒细胞。采用共聚焦激光扫描显微镜、薄切片透射电子显微镜和网格映射冷冻断裂复制免疫金标记，10个紧密贴壁揭示轴-轴间隙连接（直径约30-70 nm）之间的苔藓纤维轴突对（直径约100-200 nm），在大鼠背侧海马CA 3c区的苔藓纤维轴突上发现一个轴突间隙连接（约100个连接点）。两种大小的金珠免疫金标记显示，连接蛋白36存在于轴突间隙连接。这些超微结构数据支持计算机建模和体外电生理数据，表明轴-轴间隙连接在产生非常快（> 70 Hz）的网络振荡和癫痫的超同步电活动中起重要作用。
Gap junctions have been postulated to exist between the axons of excitatory cortical neurons based on electrophysiological, modeling, and dye-coupling data. Here, we provide ultrastructural evidence for axoaxonic gap junctions in dentate granule cells. Using combined confocal laser scanning microscopy, thin-section transmission electron microscopy, and grid-mapped freeze-fracture replica immunogold labeling, 10 close appositions revealing axoaxonic gap junctions (approximate to 30-70 nm in diameter) were found between pairs of mossy fiber axons (approximate to 100-200 nm in diameter) in the stratum lucidum of the CA3b field of the rat ventral hippocampus, and one axonal gap junction (approximate to 100 connexons) was found on a mossy fiber axon in the CA3c field of the rat dorsal hippocampus. Immunogold labeling with two sizes of gold beads revealed that connexin36 was present in that axonal gap junction. These ultrastructural data support computer modeling and in vitro electrophysiological data suggesting that axoaxonic gap junctions play an important role in the generation of very fast (> 70 Hz) network oscillations and in the hypersynchronous electrical activity of epilepsy.