Kennedy Helen J, Evans Michael G, Crawford Andrew C, Fettiplace Robert
Department of Physiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
Nat Neurosci. 2003 Aug;6(8):832-6. doi: 10.1038/nn1089.
Outer hair cells are centrally involved in the amplification and frequency tuning of the mammalian cochlea, but evidence about their transducing properties in animals with fully developed hearing is lacking. Here we describe measurements of mechanoelectrical transducer currents in outer hair cells of rats between postnatal days 5 and 18, before and after the onset of hearing. Deflection of hair bundles using a new rapid piezoelectric stimulator evoked transducer currents with ultra-fast activation and adaptation kinetics. Fast adaptation resembled the same process in turtle hair cells, where it is regulated by changes in stereociliary calcium. It is argued that sub-millisecond transducer adaptation can operate in outer hair cells under the ionic, driving force and temperature conditions that prevail in the intact mammalian cochlea.
外毛细胞在哺乳动物耳蜗的放大和频率调谐中起核心作用，但缺乏关于其在听力完全发育的动物中的转导特性的证据。在此，我们描述了出生后第5天至18天的大鼠外毛细胞在听力开始前后的机械电换能器电流测量。使用新型快速压电刺激器使毛束偏转，诱发了具有超快激活和适应动力学的换能器电流。快速适应类似于龟毛细胞中的相同过程，在龟毛细胞中，它受静纤毛钙变化的调节。有人认为，在完整的哺乳动物耳蜗中普遍存在的离子、驱动力和温度条件下，亚毫秒级的换能器适应可在外毛细胞中发挥作用。
