Detection of Cochlear Amplification and Its Activation
Detection of Cochlear Amplification and Its Activation
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DOI：
10.1016/j.bpj.2013.06.049
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发表时间：
2013-08-20
影响因子：
3.4
通讯作者：
Olson, Elizabeth S.
中科院分区：
文献类型：
--
作者：
Dong, Wei;Olson, Elizabeth S.
哺乳动物耳蜗的操作依赖于机械行波，该机械行波由感觉外毛细胞（OHC）中的机电力主动增强。这种有源耳蜗放大器产生令人印象深刻的灵敏度和哺乳动物听觉的频率分辨率。耳蜗放大器自20世纪70年代被发现以来一直激励着科学家，但仍然没有得到很好的理解。为了探索耳蜗感觉细胞/组织界面的电力学，使用最近开发的双传感器与微电极连接到微压力传感器测量声音诱发的耳蜗内压力和细胞外电压。OHC电活动、基底膜压力和基底膜位移的体内观察结果一致，为耳蜗中的功率放大提供了直接证据。此外，结果表明，在略低于峰值的频率下，在放大的开始附近，电压相对于机械响应的相移。基于孤立OHC的电压-力关系，该偏移将在行波峰内引起有效OHC泵浦力。因此，移位激活耳蜗放大器，用于定位并因此锐化放大的频率区域。这些结果是迄今为止耳蜗功率放大的最具体的证据，并支持OHC体细胞力作为其来源。
The operation of the mammalian cochlea relies on a mechanical traveling wave that is actively boosted by electromechanical forces in sensory outer hair cells (OHCs). This active cochlear amplifier produces the impressive sensitivity and frequency resolution of mammalian hearing. The cochlear amplifier has inspired scientists since its discovery in the 1970s, and is still not well understood. To explore cochlear electromechanics at the sensory cell/tissue interface, sound-evoked intracochlear pressure and extracellular voltage were measured using a recently developed dual-sensor with a microelectrode attached to a micro-pressure sensor. The resulting coincident in vivo observations of OHC electrical activity, pressure at the basilar membrane and basilar membrane displacement gave direct evidence for power amplification in the cochlea. Moreover, the results showed a phase shift of voltage relative to mechanical responses at frequencies slightly below the peak, near the onset of amplification. Based on the voltage-force relationship of isolated OHCs, the shift would give rise to effective OHC pumping forces within the traveling wave peak. Thus, the shift activates the cochlear amplifier, serving to localize and thus sharpen the frequency region of amplification. These results are the most concrete evidence for cochlear power amplification to date and support OHC somatic forces as its source.