Roles of afadin in functional differentiations of hippocampal mossy fiber synapse
Roles of afadin in functional differentiations of hippocampal mossy fiber synapse
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DOI：
10.1111/gtc.12508
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发表时间：
2017-08-01
期刊：
影响因子：
2.1
通讯作者：
Mori, Masahiro
中科院分区：
文献类型：
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作者：
Geng, Xiaoqi;Maruo, Tomohiko;Mori, Masahiro
海马苔藓纤维突触具有复杂的结构，与学习和记忆有关。在这个突触中，苔藓纤维束通过附着点连接连接到树突轴上，并围绕着多分支的脊柱，形成突触连接。我们最近使用透射电子显微镜、免疫电子显微镜和连续块面扫描电子显微镜发现，在缺乏黄嘌呤的苔藓纤维突触中形成了非典型的附着点连接，并且在缺乏黄嘌呤的突触中，突触后棘和苔藓纤维扣的复杂性、棘头的数量、突触后密度的面积和连接到活性区的突触囊泡的密度都减少了。我们在此研究了黄蜡素在苔藓纤维突触功能分化中的作用，使用黄蜡素缺乏的小鼠。电生理研究表明，谷氨酸释放概率和对谷氨酸的突触后反应性均明显降低，但未完全丧失，而长期增强和长期抑制均未受到影响。这些结果表明，黄嘌呤在海马苔藓纤维突触突触前和突触后的功能分化中起作用。
A hippocampal mossy fiber synapse has a complex structure and is implicated in learning and memory. In this synapse, the mossy fiber boutons attach to the dendritic shaft by puncta adherentia junctions and wrap around a multiply-branched spine, forming synaptic junctions. We have recently shown using transmission electron microscopy, immunoelectron microscopy and serial block face-scanning electron microscopy that atypical puncta adherentia junctions are formed in the afadin-deficient mossy fiber synapse and that the complexity of postsynaptic spines and mossy fiber boutons, the number of spine heads, the area of postsynaptic densities and the density of synaptic vesicles docked to active zones are decreased in the afadin-deficient synapse. We investigated here the roles of afadin in the functional differentiations of the mossy fiber synapse using the afadin-deficient mice. The electrophysiological studies showed that both the release probability of glutamate and the postsynaptic responsiveness to glutamate were markedly reduced, but not completely lost, in the afadin-deficient mossy fiber synapse, whereas neither long-term potentiation nor long-term depression was affected. These results indicate that afadin plays roles in the functional differentiations of the presynapse and the postsynapse of the hippocampal mossy fiber synapse.