The Caruso Department of Otolaryngology - Head & Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA.
Department of Otolaryngology - Head & Neck Surgery, Stanford University, Stanford, CA 94305, USA.
Cell Rep. 2018 Jun 5;23(10):2915-2927. doi: 10.1016/j.celrep.2018.05.024.
The stereociliary bundles of cochlear hair cells convert mechanical vibrations into the electrical signals required for auditory sensation. While the stiffness of the bundles strongly influences mechanotransduction, its influence on the vibratory response of the cochlear partition is unclear. To assess this, we measured cochlear vibrations in mutant mice with reduced bundle stiffness or with a tectorial membrane (TM) that is detached from the sensory epithelium. We found that reducing bundle stiffness decreased the high-frequency extent and sharpened the tuning of vibratory responses obtained postmortem. Detaching the TM further reduced the high-frequency extent of the vibrations but also lowered the partition's resonant frequency. Together, these results demonstrate that the bundle's stiffness and attachment to the TM contribute to passive longitudinal coupling in the cochlea. We conclude that the stereociliary bundles and TM interact to facilitate passive-wave propagation to more apical locations, possibly enhancing active-wave amplification in vivo.
耳蜗毛细胞的纤毛束将机械振动转化为听觉感觉所需的电信号。虽然束的刚度强烈影响机械转导，但它对耳蜗隔板的振动响应的影响尚不清楚。为了评估这一点，我们测量了具有降低的束刚度或与从感觉上皮分离的盖膜（TM）的突变小鼠的耳蜗振动。我们发现，降低束的刚度会减小振动的高频范围并锐化死后获得的振动调谐。进一步分离 TM 会进一步减小振动的高频范围，但也会降低隔板的共振频率。这些结果表明，束的刚度及其与 TM 的附着有助于耳蜗中的被动纵向耦合。我们得出结论，纤毛束和 TM 相互作用以促进被动波向更顶端位置的传播，可能在体内增强主动波的放大。
