链霉素对豚鼠耳蜗外毛细胞离子电流的影响

Effects of streptomycin on ionic currents in isolated outer hair cells of guinea pig cochlea

使用全细胞式记录膜片钳技术，研究链霉素对豚鼠耳蜗外毛细胞离子电流的影响。结果示：1mmol／L链霉素分别使钾电流和钙电流减少；链霉素对电压依赖性钙电流的半数抑制浓度为56.08μmol／L，最大抑制率为21．71％。表明链霉素以浓度依赖性方式、部分不可逆地阻断豚鼠耳蜗外毛细胞电压依赖性钙电流，对钾电流的阻滞作用部分是阻断Ca2+内流的结果。提示此即链霉素耳毒性产生的机理之一。

The effects of streptomycin on ionic currents in outer hair cells isolated from the cochlea of guinea pig were investigated using a whole-cell recording patch-clamp technique. External application of streptomycin (1mmol/L ) caused a decrease of the potassium currents and calcium currents,respectively. The half-maximal inhibition concentration of streptomycin checking the vol tage-dependent calcium currents was 56. 08μmol/L,and the ratio of maximal inhibition 21. 71 %.The plesent results demonstrate that streptomycin partially irreversibly blocks the voltage-depen dent calcium currents in dissociated outer hair cells of guinea pig cochlea in a concentration-depen dent manner. The effects of streptomycin of the potassium currents may be,at least in part,the result of the inhibition of Ca2+ influx. It suggests that the inhibition of Ga2+ influx may be one of the ototoxic mechanisms of streptomycin on outer hair cells.