豚鼠耳蜗外毛细胞的钾通道  

Potassium channels in outer hair cells of the guinea pig’s cochlea

作　　者：苏振伦[1] 顾瑞[1] 姜泗长[1] 

机构地区：[1]中国人民解放军总医院耳鼻咽喉科,中国人民解放军耳鼻咽喉科研究所,北京100853

出　　处：《中华耳科学杂志》2004年第3期205-209,共5页Chinese Journal of Otology

基　　金：国家自然科学基金资助项目(39970787)

摘　　要：目的研究外毛细胞钾离子通道的生物物理学和药理学特性。方法用细胞贴附式和内面向外式膜片钳技术,研究豚鼠耳蜗单离外毛细胞底侧膜的钾离子单通道电流。结果记录到两种钾离子单通道电流(1)大电导型钙激活钾通道,在等渗140mmol/LKC1溶液时电导为161±26pS(内面向外式)或155±27pS(细胞贴附式),反转电位为0mV;浴液为Hanks液而电极内液为140mmo/LKC1液时,电导为133±9pS(细胞贴附式)。当膜内面浴于无钙液时通道活动消失。通道呈簇状发放或快速簇状发放方式,其开启和关闭时程直方图均可用三阶指数方程拟合。双氢链霉素能够可逆性地抑制外毛细胞的大电导型钙激活钾通道,表现为电流幅度减少,在链霉素浓度增大以及细胞膜电位偏正时更明显,新霉素的抑制作用更强。(2)～44pS钾通道。结论豚鼠耳蜗外毛细胞底侧膜具有两种钾离子通道,研究了其大电导型钙激活钾通道的生物物理学和药理学特性。Objective To investigate the potassium channels in outer hair cells. Methods Single K+ channel currents in outer hair cells isolated from the guinea pig’s cochlea were recorded in cell-attached and excised inside-out configurations of the patch-clamp technique by using the EPC-9 amplifier and M2LAB software. Results The prevailing type of potassium channels was maxi- K+ channel with the slope conductance of 161±26 pS (mean±SD, n=8; inside-out patches) or 155±27 pS (n=4; on-cell recordings) in symmetrical 140 mM K+ solutions. The currents reversed at about 0 mV. When the bath contained Hanks’s solutions, the slope conductance was 133±9 pS (n=5; on-cell recordings). Exposing the patches to Ca2+-free solutions reversibly inhibited the channel activity, as was to aminoglycoside antibiotics. Both of the open and closed histograms were fitted by the sum of three decaying exponential functions. Another type of potassium channels was also detected with a unitary conductance of ～44 pS . Conclusion Two types of potassium channels were detected in outer hair cells of the guinea pig’s cochlea. One of them was identified as the maxi- K+ channel and its biophysical and pharmacological properties were investigated in detail.

关 键 词：豚鼠 耳蜗 外毛细胞 钾通道 生物物理学 药理学特性 氨基糖甙类抗生素 膜片钳记录 

分 类 号：R764[医药卫生—耳鼻咽喉科]