Huang G, Santos-Sacchi J
Section of Otolaryngology, Yale University School of Medicine, New Haven, CT 06510.
Proc Natl Acad Sci U S A. 1994 Dec 6;91(25):12268-72. doi: 10.1073/pnas.91.25.12268.
The outer hair cell (OHC) from the organ of Corti is believed to be responsible for the mammal's exquisite sense of hearing. A membrane-based motile response of this cell underlies the initial processing of acoustic energy. The voltage-dependent capacitance of the OHC, possibly reflecting charge movement of the motility voltage sensor, was measured in cells during intracellular dialysis of trypsin under whole cell voltage clamp. Within 10 min after dialysis, light and electron microscopic examination revealed that the subplasmalemmal structures, including the cytoskeletal framework and subsurface cisternae, were disrupted and/or detached from adjacent plasma membrane. Dialysis of heat-inactivated trypsin produced no changes in cell structure. Simultaneous measures of linear and nonlinear membrane capacitance revealed minimal changes, indicating that contributions by subsurface structures to the generation of the nonlinear capacitance are unlikely. This study strongly suggests that voltage-dependent charge movement in the OHC reflects properties of the force generator's voltage sensor and that the sensor/motor resides solely within the lateral plasma membrane.
柯蒂氏器的外毛细胞（OHC）被认为是哺乳动物敏锐听觉的关键所在。该细胞基于膜的运动反应是声能初始处理的基础。在全细胞膜片钳下对细胞进行胰蛋白酶细胞内透析时，测量了OHC的电压依赖性电容，其可能反映了运动电压传感器的电荷移动。透析后10分钟内，光学和电子显微镜检查显示，包括细胞骨架框架和表面下池在内的质膜下结构被破坏和/或与相邻质膜分离。热灭活胰蛋白酶的透析未引起细胞结构变化。线性和非线性膜电容的同步测量显示变化极小，这表明表面下结构对非线性电容产生的贡献不大。这项研究有力地表明，OHC中电压依赖性电荷移动反映了力发生器电压传感器的特性，并且传感器/马达仅存在于外侧质膜内。
