Auditory Input Shapes Tonotopic Differentiation of Kv1.1 Expression in Avian Cochlear Nucleus during Late Development
Auditory Input Shapes Tonotopic Differentiation of Kv1.1 Expression in Avian Cochlear Nucleus during Late Development
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DOI：
10.1523/jneurosci.2472-17.2018
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发表时间：
2018-03-21
影响因子：
5.3
通讯作者：
Kuba, Hiroshi
中科院分区：
文献类型：
--
作者：
Akter, Nargis;Adachi, Ryota;Kuba, Hiroshi
纯音辨别是听觉系统信号处理的基础。然而，这种差异何时以及如何出现仍然难以捉摸。我们用电生理学和免疫组织化学的方法在两性鸡的大细胞核中解决了这个问题，已知Kv1.1通道的表达取决于特征频率(Cf)。在听力开始后(胚胎第12-14天)，在高Cf的神经元上，KV1电流逐渐增加，幅度略大，导致孵化前KV1电流的电位性差异。然而，孵化后，由于Kv1.1在质膜上的表达增强，Kv1电流发生了更大的增加，尤其是在高CF神经元。这种后来的表达变化导致了成熟动物KV1电流特征的大的调位差异。通过诱导舱口周围的传导性或感觉神经性听力损失来抑制听觉输入的衰减以一种水平依赖的方式抑制分化。此外，胚胎期间听觉输入的增加不能再现分化，这表明神经元通过听觉输入驱动Kv1.1表达的能力是以细胞特有的方式发展的，从而奠定了核内通道频率特异性表达的基础。结果表明，Kv1.1在大细胞核内的定位分化在孵化前部分决定，但在孵化后很大程度上由传入输入驱动。我们的结果强调了神经元对声音的能力对驱动离子通道表达的重要性，以及在脑干听觉回路的频率调谐中听觉体验的水平。
Tonotopic differentiation is fundamental for signal processing in the auditory system. However, when and how this differentiation arises remain elusive. We addressed this issue using electrophysiology and immunohistochemistry in nucleus magnocellularis of chickens of both sexes, which is known to differ in the expression of Kv1.1 channels depending on characteristic frequency (CF). Just after hearing onset (embryonic day 12-14), Kv1 current gradually increased to a slightly larger extent in neurons with higher CF, causing a tonotopic difference of Kv1 current before hatch. However, after hatch, a much larger increase of Kv1 current occurred, particularly in higher-CF neurons, due to an augmentation of Kv1.1 expression at the plasma membrane. This later change in expression led to the large tonotopic difference of Kv1 current characteristic of mature animals. Attenuation of auditory input by inducing conductive or sensorineural hearing loss around hatch suppressed the differentiation in a level-dependent manner. Moreover, elevation of auditory input during embryonic periods could not reproduce the differentiation, suggesting that the capacity of neurons to drive Kv1.1 expression via auditory input develops in a cell-specific manner, thus underlying the frequency-specific expression of the channel within the nucleus. The results indicated that the tonotopic differentiation of Kv1.1 in nucleus magnocellularis is partially determined before hatch, but largely driven by afferent input after hatch. Our results highlight the importance of neuronal capacity for sound to drive ion channel expression as well as the level of auditory experience in the frequency tuning of brainstem auditory circuits.