Evans B N, Dallos P
Auditory Physiology Laboratory, Hugh Knowles Center, Northwestern University, Evanston, IL 60208.
Proc Natl Acad Sci U S A. 1993 Sep 15;90(18):8347-51. doi: 10.1073/pnas.90.18.8347.
Outer hair cells, isolated from mammalian cochleas, are known to respond to electrical stimulation with elongation or contraction of the cell's cylindrical soma. It is assumed that such shape changes, when driven by the cell's receptor potential in vivo, are a part of the feedback process that underlies cochlear amplification. To date it has not been possible to demonstrate somatic shape changes upon normal mechanical stimulation of the cell--i.e., the deflection of its hair bundle. We show here that mechanically induced hair-bundle deflection produces somatic motility of the cell. Such motility is dependent upon a functioning forward transducer process and disappears upon interference with transduction. The motile response also reflects the hair bundle's known directional sensitivity. This demonstration of mechanically driven motility indicates that the cell may possess capabilities to affect its mechanical environment under control of its own receptor potential and, thereby, participate in a local cochlear feedback process.
从哺乳动物耳蜗分离出的外毛细胞，已知会对电刺激产生反应，其柱状胞体伸长或收缩。据推测，在体内由细胞受体电位驱动时，这种形状变化是构成耳蜗放大基础的反馈过程的一部分。迄今为止，尚无法证明在对细胞进行正常机械刺激时——即其毛束的偏转——会发生胞体形状变化。我们在此表明，机械诱导的毛束偏转可产生细胞的胞体运动。这种运动依赖于正常运作的正向换能过程，在换能受到干扰时消失。运动反应也反映了毛束已知的方向敏感性。这种机械驱动运动的证明表明，细胞可能具备在自身受体电位控制下影响其机械环境的能力，从而参与局部耳蜗反馈过程。
