Imaging hair cell transduction at the speed of sound: Dynamic behavior of mammalian stereocilia
Imaging hair cell transduction at the speed of sound: Dynamic behavior of mammalian stereocilia
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DOI：
10.1073/pnas.0507231103
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发表时间：
2006-02-07
影响因子：
11.1
通讯作者：
de Monvel, JB
中科院分区：
文献类型：
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作者：
Fridberger, A;Tomo, I;de Monvel, JB
耳蜗包含两种类型的感觉细胞，即内毛细胞和外毛细胞。声音引起的外毛细胞静纤毛的偏转导致快速的力产生，这将增强听觉灵敏度高达1,000倍。相比之下，内毛细胞被认为具有纯粹的接受功能。静纤毛的偏转在听神经中产生受体电位、递质释放和动作电位。在这里，我们描述了一种快速共焦成像的方法。该方法被用来形象静纤毛同时声刺激在豚鼠耳蜗的体外制备。我们表明，内毛细胞静纤毛移动，因为它们与周围的毛束的流体相互作用，但静纤毛偏转发生在不同的阶段的刺激比一般预期的。在外毛细胞中，静纤毛偏转约为网状板位移的1/3。内毛细胞的偏转较小。静纤毛偏转和网状板位移之间的比率对于听觉功能是重要的，因为它决定了施加到转导通道的刺激。这里测量的低比率表明，放大的毛束运动可能是必要的在体内保持在低刺激水平下的转导保真度。在内毛细胞的情况下，这一发现将代表对它们功能的传统观点的偏离。
The cochlea contains two types of sensory cells, the inner and outer hair cells. Sound-evoked deflection of outer hair cell stereocilia leads to fast force production that will enhance auditory sensitivity up to 1,000-fold. In contrast, inner hair cells are thought to have a purely receptive function. Deflection of their stereocilia produces receptor potentials, transmitter release, and action potentials in the auditory nerve. Here, we describe a method for rapid confocal imaging. The method was used to image stereocilia during simultaneous sound stimulation in an in vitro preparation of the guinea pig cochlea. We show that inner hair cell stereocilia move because they interact with the fluid surrounding the hair bundles, but stereocilia deflection occurs at a different phase of the stimulus than is generally expected. In outer hair cells, stereocilia deflections were approximate to 1/3 of the reticular lamina displacement. Smaller deflections were found in inner hair cells. The ratio between stereocilia deflection and reticular lamina displacement is important for auditory function, because it determines the stimulus applied to transduction channels. The low ratio measured here suggests that amplification of hair-bundle movements may be necessary in vivo to preserve transduction fidelity at low stimulus levels. In the case of the inner hair cells, this finding would represent a departure from traditional views on their function.