Passive compliance and active force generation in the guinea pig outer hair cell
Passive compliance and active force generation in the guinea pig outer hair cell
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DOI：
10.1152/jn.1995.74.6.2319
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发表时间：
1995-12-01
影响因子：
2.5
通讯作者：
Hallworth, R
中科院分区：
文献类型：
--
作者：
Hallworth, R
1.在体外使用安装在压电致动器上的校准玻璃纤维轴向压缩长度为20-80 μ m的耳蜗外毛细胞。当在压缩方向上由矩形脉冲驱动时，纤维尖端的运动包括在10-20 ms内完成的快速初始压缩，随后是较慢时间过程的较小压缩.最初的纤维偏转被发现是线性的振幅压缩到400 nm。外毛细胞的轴向顺应性是从纤维尖端运动之间的差异计算的，当未连接时，当与细胞接触时。149个电池的轴向顺应性在0.04-1.2 km/ N的范围内。轴向顺应性是细胞长度的递增函数.由电刺激的外毛细胞产生的峰值力是从玻璃纤维的偏转测量的，当细胞被正弦电压命令刺激时。力产生的斜率增益（在细胞膜处每mV命令产生的力）估计为0.01至100 pN/mV。大多数结果落在0.1-20 pN/mV.5的范围内。当通过移动细胞更靠近纤维基底来增加纤维的表观刚度时，对于相同的正弦电压指令，由细胞产生的纤维偏转的峰值幅度减小，峰值力增加.前面实验的结果被解释在光的外毛细胞运动的模型中，其中一个理想的扩展生成元件是串联的内部刚度元件。然后计算13个单元的内部刚度。通过上述程序计算的单元的内部刚度被发现与相同单元获得的轴向刚度测量值正相关。上述结果的影响外毛细胞在体内运动的有效性进行了讨论。
1. Cochlear outer hair cells 20-80 mu m in length were compressed axially in vitro using calibrated glass fibers mounted on a piezoelectric actuator.2. When driven by rectangular pulses in the compression direction, the motion of the fiber tip consisted of a rapid initial compression that was complete in 10-20 ms followed by a smaller compression of slower time course.3. The initial fiber deflections were found to be linear in amplitude for compressions up to 400 nm. The axial compliances of outer hair cells were calculated from the difference between the fiber tip motions when unattached and when in contact with a cell. Axial compliances were found to be in the range of 0.04-1.2 km/ N for 149 cells. The axial compliance was an increasing function of cell length.4. The peak forces generated by electrically stimulated outer hair cells were measured from the deflection of a glass fiber when the cells were stimulated by sinusoidal voltage commands. The slope gains of force generation (force generated per mV of command at the cell membrane) were estimated to range from 0.01 to 100 pN/mV. Most of the results fell in the range of 0.1-20 pN/mV.5. When the apparent stiffness of the fiber was increased by moving the cell closer to the fiber base, the peak amplitude of the fiber deflection generated by the cell decreased and the peak force increased, for the same sinusoidal voltage command.6. The results of the previous experiment were interpreted in the light of a model of outer hair cell motility in which an ideal extension generating element is in series with an internal stiffness element. This internal stiffness was then calculated for 13 cells.7. The internal stiffnesses of cells calculated by the above procedure were found to be positively correlated with the axial stiffness measurements obtained for the same cells.8. The implications of the above results for the effectiveness of outer hair cell motility in vivo are discussed.