K_v3 family K⁺ channels, by ensuring speedy repolarization of action potential, enable rapid and high frequency neuronal firing and high precision temporal coding of auditory information in various auditory synapses in the brain. Expression of different K_v3 subtypes within the auditory end organ has been reported. Yet, their precise role at the hair cell synaptic transmission has not been fully elucidated. Using immunolabeling and confocal microscopy we examined the expression pattern of different K_v3 family K⁺ channel subunits in the nerve fibers innervating the cochlear hair cells. K_v3.1b was found in NKA-positive type 1 afferent fibers, exhibiting high signal intensity at the cell body, the unmyelinated dendritic segment, first heminode and nodes of Ranvier. K_v3.3 signal was detected in the cell body and the unmyelinated dendritic segment of NKA-positive type 1 afferent fibers but not in peripherin-positive type 2 afferent. K_v3.4 was found in ChAT-positive LOC and MOC efferent fibers as well as peripherin-positive type 2 afferent fibers. Such segregated expression pattern implies that each K_v3 subunits participate in different auditory tasks, for example, K_v3.1b and K_v3.3 in ascending signaling while K_v3.4 in feedback upon loud noise exposure.

中文翻译：

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耳蜗传入神经纤维和传出神经纤维中Kv3亚基的分布暗示在听觉加工中的不同作用。

K _v 3家族K ⁺通道通过确保动作电位的快速复极化，使得大脑中各种听觉突触中的听觉信息能够进行快速，高频的神经元放电和高精度的时间编码。已经报道了在听觉末端器官中不同K _v 3亚型的表达。但是，它们在毛细胞突触传递中的确切作用尚未完全阐明。使用免疫标记和共聚焦显微镜，我们检查了支配耳蜗毛细胞的神经纤维中不同K _v 3家族K ⁺通道亚单位的表达模式。ķ _v在NKA阳性1型传入纤维中发现了3.1b，在细胞体，未髓鞘的树突节，第一个血鳞和Ranvier结节上显示出高信号强度。在细胞体和NKA阳性1型传入纤维中未髓鞘状的树突节中检测到K _v 3.3信号，但在2型外周蛋白阳性传入纤维中未检测到K _v 3.3信号。在ChAT阳性LOC和MOC传入纤维以及周围蛋白阳性2型传入纤维中发现K _v 3.4。这种分离的表达模式意味着每个K _v 3个亚基参与不同的听觉任务，例如，K _v 3.1b和K _v 3.3参与上行信号传递，而K _v 3.4参与大声噪声反馈。