Tuning of synapse number, structure and function in the cochlea
Tuning of synapse number, structure and function in the cochlea
复制标题
DOI：
10.1038/nn.2293
复制
发表时间：
2009-04-01
影响因子：
25
通讯作者：
Moser, Tobias
中科院分区：
文献类型：
--
作者：
Meyer, Alexander C.;Frank, Thomas;Moser, Tobias
耳蜗内毛细胞通过带状突触向螺旋神经节神经元传递声学信息。在这里，我们使用了形态和生理学技术来询问是否突触机制在小鼠耳蜗单侧轴和IHC内有所不同。我们发现，每个IHC的带状突触数量在耳蜗对声音最敏感的地方达到峰值。胞吐作用是通过膜电容的变化来测量的，当比较顶端和中段的IHC时，根据突触数量来衡量。突触分布于IHCs的核下部。IHC突触的高分辨率成像提供了对突触前Ca~(2+)通道簇和Ca~(2+)信号、突触带和突触后谷氨酸受体簇的洞察，并揭示了它们在紧张轴方向的平均特性的细微差异。然而，我们观察到突触前Ca~(2+)信号的显著差异，甚至在单个IHC中也是如此，这为螺旋神经节神经元放电的发散动力学提供了一个候选的突触前机制。
Cochlear inner hair cells (IHCs) transmit acoustic information to spiral ganglion neurons through ribbon synapses. Here we have used morphological and physiological techniques to ask whether synaptic mechanisms differ along the tonotopic axis and within IHCs in the mouse cochlea. We show that the number of ribbon synapses per IHC peaks where the cochlea is most sensitive to sound. Exocytosis, measured as membrane capacitance changes, scaled with synapse number when comparing apical and midcochlear IHCs. Synapses were distributed in the subnuclear portion of IHCs. High-resolution imaging of IHC synapses provided insights into presynaptic Ca2+ channel clusters and Ca2+ signals, synaptic ribbons and postsynaptic glutamate receptor clusters and revealed subtle differences in their average properties along the tonotopic axis. However, we observed substantial variability for presynaptic Ca2+ signals, even within individual IHCs, providing a candidate presynaptic mechanism for the divergent dynamics of spiral ganglion neuron spiking.