Reuter G, Gitter A H, Thurm U, Zenner H P
Department of Otolaryngology, University of Tübingen, FRG.
Hear Res. 1992 Jul;60(2):236-46. doi: 10.1016/0378-5955(92)90025-i.
Recently, it was shown in cochlear explants from the guinea pig cochlea that electrokinetic motile responses of outer hair cells can induce radial and transverse motion of the reticular lamina. Here we demonstrate, that the radial component of these motions can be measured up to high frequencies (15 kHz). Cochlear explants were taken from guinea pig inner ears and exposed to a sinusoidal electric field. A double photodiode was used as a linear position detector with high spatial and temporal resolution to detect radial movements in the plane of the reticular lamina. The organ of Corti of the second, third and fourth cochlear turns was stimulated with frequencies of the electrical field between 0.5 Hz and 20 kHz. Sinusoidal movements of up to 15 kHz were recorded. At higher frequencies the signal-to-noise ratio became too small. The largest responses were measured at the three rows of outer hair cells. If the strength of the electrical field was 2 kV/m, into which the cochlear explants were placed, the amplitudes of outer hair cell movements were around 1 micron at 1 Hz and 10 nm at 10 kHz. Uncoupling of the outer hair cells from the tunnel of Corti and from the inner hair cells decreased the oscillations of inner hair cells but did not affect outer hair cells. The movements showed frequency dependent amplitudes like a complex low-pass filter but no best frequency was observed.
最近，在豚鼠耳蜗的耳蜗外植体中发现，外毛细胞的电动运动反应可引起网状板的径向和横向运动。在此我们证明，这些运动的径向分量可测量到高频（15千赫兹）。从豚鼠内耳获取耳蜗外植体，并将其暴露于正弦电场中。使用双光电二极管作为具有高空间和时间分辨率的线性位置检测器，以检测网状板平面内的径向运动。用0.5赫兹至20千赫兹的电场频率刺激第二、第三和第四耳蜗转的柯蒂氏器。记录到高达15千赫兹的正弦运动。在更高频率下，信噪比变得太小。在三排外毛细胞处测得最大反应。如果将耳蜗外植体置于强度为2千伏/米的电场中，外毛细胞运动的幅度在1赫兹时约为1微米，在10千赫兹时为10纳米。外毛细胞与柯蒂氏隧道和内毛细胞的解偶联减少了内毛细胞的振荡，但不影响外毛细胞。这些运动表现出像复杂低通滤波器一样的频率依赖性幅度，但未观察到最佳频率。
