Electromotility in outer hair cells: A supporting role for fast potassium conductance
Electromotility in outer hair cells: A supporting role for fast potassium conductance
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DOI：
10.1159/000095280
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发表时间：
2006-01-01
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影响因子：
--
通讯作者：
Iwasa, Kuni H.
中科院分区：
文献类型：
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作者：
Ospeck, Mark;Dong, Xiao-Xia;Iwasa, Kuni H.
外耳毛细胞的运动是耳蜗放大器的基础，耳蜗放大器对耳朵的灵敏度和微调至关重要。在这些细胞存在的两种运动机制中，外侧壁的电运动性取决于受体电位，因此取决于通过细胞体的电流。我们发现，在豚鼠耳蜗中，基转外毛细胞具有快速激活的离子电流（23℃时tau < 0.3 ms），而这在顶转细胞中是不存在的。这一发现与我们之前的理论分析一致，即快速激活的钾电流只需要在基底转中抵消电容电流，从而提高电动力的有效性。因此，我们的发现与电动力的功能意义是一致的。因此，我们推测，电流降低了外毛细胞的电容，以增加听力带宽。版权所有(c) 2006 S. Karger AG，巴塞尔。
Motility of outer hair cells underlies the cochlear amplifier, which is critical for the ear's sensitivity and fine tuning. Of the two motile mechanisms present in these cells, electromotility at the lateral wall depends on the receptor potential and thus depends on currents through the cell body. We found that, in the guinea pig cochlea, basal turn outer hair cells have a fast-activating ion current (tau < 0.3 ms at 23 degrees C), which is absent in apical turn cells. This finding is consistent with our previous theoretical analysis that a fast-activating potassium current is required only in the basal turn to counteract the capacitive current and thereby to enhance the effectiveness of electromotility. Thus, our finding is consistent with the functional significance of electromotility. We conjecture therefore that the current reduces the capacitance of the outer hair cell in order to increase hearing bandwidth. Copyright (c) 2006 S. Karger AG, Basel.