Transient expression of an inwardly rectifying potassium conductance in developing inner and outer hair cells along the mouse cochlea
Transient expression of an inwardly rectifying potassium conductance in developing inner and outer hair cells along the mouse cochlea
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DOI：
10.1007/s004240051134
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发表时间：
1999-12-01
影响因子：
4.5
通讯作者：
Kros, CJ
中科院分区：
文献类型：
--
作者：
Marcotti, W;Géléoc, GSG;Kros, CJ
本文研究了小鼠耳蜗纳塔尔后发育过程中内、外毛细胞（IHC、OHC）的抑制整流钾电流。超极化步骤：从-64 mV的保持电位开始，在两种细胞类型中诱导快速激活电流。该电流在Kt平衡电位附近表现出强烈的内向整流，在电位负至-130 mV时，部分失活。激活范围随细胞外K+浓度的变化而变化。外源性Ba ~（2+）和Cs ~（2+）可可逆性阻断该电流。这些结果是一致的存在下，I-K1型内向整流钾电导在这些细胞。I-K1的最大电流在耳蜗毛细胞中比在耳蜗毛细胞中大60%;在耳蜗毛细胞中，I-K1的幅度随细胞沿着耳蜗的位置而显著变化，但在耳蜗毛细胞中则无此现象。I-K1在位于耳蜗最基底区的细胞中最大，其幅度在顶端线圈中降低。I-K1消失后的功能成熟：在OHC在出生后第一周结束时，在IHC在出生后12天的听觉功能的发作。电流在细胞的静息电位下是活跃的，并且在调节发育中的毛细胞的尖峰行为特征中起作用。
Inwardly rectifying K+ currents in inner and outer hair cells (IHCs, OHCs) were studied during post natal development of the mouse cochlea. Hyperpolarizing steps: from a holding potential of -64 mV induced a rapidly activating current in both cell types. This current showed strong inward rectification around the Kt equilibrium potential and, at potentials negative to -130 mV, partial inactivation. The activation range varied with extracellular K+ concentration. External application of Ba2+ and Cs+ reversibly blocked the elicited current. The results are consistent with the presence of an I-K1-type inwardly rectifying potassium conductance in these cells. The maximum current was 60% larger in IHCs than in OHCs; In OHCs, but not IHCs, the amplitude of I-K1 varied significantly with the cells' position along the cochlea. I-K1 was maximal in cells located in the most basal region of the cochlea and its amplitude decreased in the apical coil. I-K1 disappeared upon functional maturation: in OHCs at the end of the first postnatal week, and in IHCs at the onset of auditory function 12 days after birth. The current is active at the resting potential of the cells and plays a role in regulating the spiking behaviour characteristic of developing hair cells.