Otoacoustic emissions without somatic motility: Can stereocilia mechanics drive the mammalian cochlea?
Otoacoustic emissions without somatic motility: Can stereocilia mechanics drive the mammalian cochlea?
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DOI：
10.1121/1.1775275
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发表时间：
2004-09-01
影响因子：
2.4
通讯作者：
Guinan, JJ
中科院分区：
文献类型：
--
作者：
Liberman, MC;Zuo, J;Guinan, JJ
低电平音调引起的失真产物耳声发射 (DPOAE) 是外毛细胞 (OHC) 功能的敏感指标。高水平的 DPOAE 不太容易受到耳蜗损伤，并且它们对 OHC 功能的依赖更具争议性。在这里，使用缺乏 prestin 的突变小鼠系解决了高水平 DPOAE 生成的机制，prestin 是驱动 OHC 体细胞运动的分子马达，是耳蜗放大所需的。通过删除 prestin，可以在高声级下测量减弱的 DPOAE。 DPOAE 阈值偏移了大约 50 dB，与复合动作电位中测量的耳蜗放大器增益的损失相匹配。相反，在高声级下，突变体的耳蜗微音（CM）中的失真产物相对于野生型没有减少（在原色处表达为 re CM）。 CM 和耳声发射中的失真产物在死亡后迅速消失。结果表明，OHC 体细胞运动对于高 SPL 下 DPOAE 的产生不是必需的。他们还表明，仍然没有基于 prestin 的运动性的小的、生理上脆弱的 DPOAE 直接归因于与静纤毛转导相关的机械非线性，并且这种静纤毛机械非线性与耳蜗分区的运动紧密耦合，达到可以驱动中耳的程度。 (C) 2004 年美国声学学会。
Distortion product otoacoustic emissions (DPOAEs) evoked by low-level tones are a sensitive indicator of outer hair cell (OHC) function. High-level DPOAEs are less vulnerable to cochlear insult, and their dependence on the OHC function is more controversial. Here, the mechanism underlying high-level DPOAE generation is addressed using a mutant mouse line lacking prestin, the molecular motor driving OHC somatic motility, required for cochlear amplification. With prestin deletion, attenuated DPOAEs were measurable at high sound levels. DPOAE thresholds were shifted by similar to50 dB, matching the loss of cochlear amplifier gain measured in compound action potentials. In contrast, at high sound levels, distortion products in the cochlear microphonic.(CM) of mutants were not decreased re wildtypes (expressed re CM at the primaries). Distortion products in both CM and otoacoustic emissions disappeared rapidly after death. The results show that OHC somatic motility is not necessary for the production of DPOAEs at high SPLs. They also suggest that the small, physiologically vulnerable DPOAE that remains without prestin-based motility is due directly to the mechanical nonlinearity associated with stereociliary transduction, and that this stereocilia mechanical nonlinearity is robustly coupled to the motion of the cochlear partition to the extent that it can drive the middle ear. (C) 2004 Acoustical Society of America.