Chan E, Ulfendahl M
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Hear Res. 1999 Feb;128(1-2):166-74. doi: 10.1016/s0378-5955(98)00207-x.
Outer hair cells isolated from the mammalian hearing organ have been shown to respond to mechanical stimuli at acoustic frequencies by expressing a change in cell length (e.g. Canlon et al., 1988). The acoustically evoked response is characterised by both a tonic length change following the envelope of the stimulus, and a frequency-dependent phasic component. We show here that mechanical stimulation at much lower frequencies directed at the cell body also elicits length changes of the outer hair cells. When the apical pole of isolated outer hair cells was compressed with a quartz fibre, a shortening or contraction at the basal pole was observed. Transverse indentation at the lateral membrane elicited shortenings at both ends of the cells. The sensitivity to the mechanical manipulation was changed by an altered tonicity of the external solution, or exposure to salicylate. As the response occurs at very low stimulus frequencies, it may account for the mechanism by which the hearing organ responds to the low frequency modulation component in complex signals like speech.
从哺乳动物听觉器官分离出的外毛细胞已被证明，通过表现出细胞长度的变化，能在声频下对机械刺激做出反应（例如，Canlon等人，1988年）。声诱发反应的特征在于，既有跟随刺激包络的持续性长度变化，也有频率依赖性的相位成分。我们在此表明，针对细胞体的低得多频率的机械刺激也会引发外毛细胞的长度变化。当用石英纤维压缩分离出的外毛细胞的顶端极时，会观察到基部极处的缩短或收缩。侧膜处的横向压痕会引起细胞两端的缩短。外部溶液张力的改变或水杨酸盐的暴露会改变对机械操作的敏感性。由于该反应在非常低的刺激频率下发生，它可能解释了听觉器官对语音等复杂信号中的低频调制成分做出反应的机制。
