Santos-Sacchi J, Wu M, Kakehata S
Section of Otolaryngology, Department of Surgery (Otolaryngology), BML 244, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06510, USA.
Hear Res. 2001 Sep;159(1-2):69-73. doi: 10.1016/s0378-5955(01)00321-5.
The outer hair cell (OHC) from the organ of Corti plays a crucial role in hearing through its unique voltage-dependent mechanical responses. Furosemide, one of the loop diuretics, disrupts normal cochlear function. Here we report on direct effects of furosemide on OHC motility-related, voltage-dependent capacitance using the whole-cell patch-clamp technique. Extracellularly applied furosemide reversibly shifted the voltage at peak capacitance (V(pkC(m))) to positive levels. The shift, whose maximum approached 90 mV, evidenced a Hill coefficient of 1.5 and K(1/2) of 10 mM. Changes in the magnitude of nonlinear capacitance were not fully reversible. While it is clear that the overwhelming effect of furosemide on hearing results via its effects on the endolymphatic potential, the present results indicate that furosemide directly alters OHC motility and may, in part, contribute to sensory dysfunction.
柯蒂氏器中的外毛细胞（OHC）通过其独特的电压依赖性机械反应在听力中发挥关键作用。速尿是一种袢利尿剂，会破坏正常的耳蜗功能。在此，我们使用全细胞膜片钳技术报告速尿对OHC运动相关的电压依赖性电容的直接影响。细胞外应用速尿可使电容峰值电压（V(pkC(m))）可逆地向正向偏移。这种偏移的最大值接近90 mV，希尔系数为1.5，半最大效应浓度（K(1/2)）为10 mM。非线性电容大小的变化并非完全可逆。虽然很明显速尿对听力的压倒性影响是通过其对内淋巴电位的作用产生的，但目前的结果表明速尿直接改变OHC的运动，并且可能部分导致感觉功能障碍。
