The effects of the activation of the inner-hair-cell basolateral K+ channels on auditory nerve responses
The effects of the activation of the inner-hair-cell basolateral K+ channels on auditory nerve responses
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DOI：
10.1016/j.heares.2018.03.029
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发表时间：
2018-07-01
期刊：
影响因子：
2.8
通讯作者：
Verhulst, Sarah
中科院分区：
文献类型：
--
作者：
Altoe, Alessandro;Pulkki, Ville;Verhulst, Sarah
哺乳动物内毛细胞（IHC）的基底外侧膜表达大的电压和Ca 2+门控外向K+电流。为了量化K+通道的电压依赖性激活如何影响支配IHC的听神经的功能，本研究采用了一种机械-神经转导模型，其中IHC的基底外侧K+电导可以是电压依赖性的或非电压依赖性的。该模型表明，K+通道的电压依赖性激活（i）增强了听觉纤维（AF）响应的锁相特性;（ii）使听觉神经能够编码大动态范围的声级;（iii）使AF响应与调幅刺激的包络精确同步;（iv）负责AF的陡峭偏移响应。这些结果表明，基底外侧K+通道发挥了重要作用，在确定众所周知的响应特性的AF和挑战经典的观点，描述了IHC膜作为一个电低通滤波器。与先前的IHC-AF复合体模型相反，本研究将许多AF反应特性归因于IHC膜中相当基本的机制，而不是突触中的复杂机制。(C)2018 Elsevier B. V.版权所有。
The basolateral membrane of the mammalian inner hair cell (IHC) expresses large voltage and Ca2+ gated outward K+ currents. To quantify how the voltage-dependent activation of the K+ channels affects the functionality of the auditory nerve innervating the IHC, this study adopts a model of mechanical-to-neural transduction in which the basolateral K+ conductances of the IHC can be made voltage-dependent or not. The model shows that the voltage-dependent activation of the K+ channels (i) enhances the phase-locking properties of the auditory fiber (AF) responses; (ii) enables the auditory nerve to encode a large dynamic range of sound levels; (iii) enables the AF responses to synchronize precisely with the envelope of amplitude modulated stimuli; and (iv), is responsible for the steep offset responses of the AFs. These results suggest that the basolateral K+ channels play a major role in determining the well-known response properties of the AFs and challenge the classical view that describes the IHC membrane as an electrical low-pass filter. In contrast to previous models of the IHC-AF complex, this study ascribes many of the AF response properties to fairly basic mechanisms in the IHC membrane rather than to complex mechanisms in the synapse. (C) 2018 Elsevier B.V. All rights reserved.