Firing features and potassium channel content of murine spiral ganglion neurons vary with cochlear location
Firing features and potassium channel content of murine spiral ganglion neurons vary with cochlear location
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DOI：
10.1002/cne.10244
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发表时间：
2002-06-10
影响因子：
2.5
通讯作者：
Davis, RL
中科院分区：
文献类型：
--
作者：
Adamson, CL;Reid, MA;Davis, RL
来自中枢神经系统不同区域的神经元对电刺激表现出截然不同的反应，这是由离子通道组成的细胞特异性差异决定的。秩序良好且高度特征化的外周听觉系统使人们能够在出生后发育的最后阶段探索这种多样性的重要性。我们在体外检查了小鼠螺旋神经节神经元的电生理特征，当时可以在髓鞘形成之前从细胞体进行记录。这些细胞携带来自基底膜毛细胞受体的声音刺激信息，并按音调排列。通过全细胞电流钳记录评估螺旋神经节神经元对去极化电流注射的反应，所述全细胞电流钳记录从小鼠耳蜗的顶端和基底三分之一处分离出来。这些细胞的放电表现出系统性的变化。顶端神经元（低频编码）表现出较长的潜伏期，缓慢适应反应，而基底神经元（高频编码）表现出较短的潜伏期，对相同刺激快速适应反应。这种生理多样性反映在免疫组织化学评估的离子通道含量的区域差异上。顶端神经元具有大量的 Kv4.2 亚基，而基底神经元则具有较高水平的 K-Ca、Kv1.1 和 Kv3.1 亚基。综上所述，这些结果表明一组电压门控钾通道的分布可能与特定的编码频率范围具体相关。这些研究还表明，螺旋神经节神经元的内在特性可能有助于外周听觉系统的特征反应。讨论了它们在发育和成人功能中的潜在作用。 (C) 2002 Wiley-Liss, Inc.
Neurons from varied regions of the central nervous system can show widely divergent responses to electrical stimuli that are determined by cell-specific differences in ion channel composition. The well-ordered and highly characterized peripheral auditory system allows one to explore the significance of this diversity during the final stages of postnatal development. We examined the electrophysiological features of murine spiral ganglion neurons in vitro at a time when recordings could be made from the cell bodies before myelination. These cells carry information about sound stimuli from hair cell receptors in the basilar membrane and are arranged tonotopically. Spiral ganglion neuron responses to depolarizing current injection were assessed with whole-cell current clamp recordings from cells that were isolated separately from the apical and basal thirds of the mouse cochlea. These cells displayed systematic variation in their firing. Apex neurons (low frequency coding) showed longer latency, slowly adapting responses, whereas base neurons (high frequency coding) showed short latency, rapidly adapting responses to the same stimuli. This physiological diversity was mirrored by regional differences in ion channel content assessed immunohistochemically. Apex neurons had a preponderance of Kv4.2 subunits, whereas base neurons possessed greater levels of K-Ca, Kv1.1, and Kv3.1 subunits. Taken together, these results indicate that the distribution of a set of voltage-gated potassium channels may relate specifically to a particular range of coding frequencies. These studies also suggest that intrinsic properties of spiral ganglion neurons can contribute to the characteristic responses of the peripheral auditory system. Their potential role in development and adult function is discussed. (C) 2002 Wiley-Liss, Inc.