Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds
Functional recovery of anterior semicircular canal afferents following hair cell regeneration in birds
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DOI：
10.1007/s101620020018
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发表时间：
2002-06-01
影响因子：
2.4
通讯作者：
Xu, JP
中科院分区：
文献类型：
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作者：
Boyle, R;Highstein, SM;Xu, JP
硫酸链霉素（1.2 g/kg i.m.）对5-7日龄的白色来航鸡连续给药5天;这导致半规管毛细胞的损伤，所述毛细胞最终再生以改革感觉上皮。在恢复期间，电生理记录采取顺序从前半规管初级传入使用压痕刺激的运河，已被证明是模仿旋转刺激。根据给药后天数，将雏鸡分配至早期（14-18天; n = 8）、中期（28-34天; n = 5）和晚期（38-58天; n = 4）。7只未处理的15-67日龄雏鸡提供对照数据。背景和indent-induced放电的情况下，在早期传入的突出特点：只有“沉默”传入的5/8实验中遇到。在这些小鸡中的几个中，传入纤维束被认为延伸到没有毛细胞的上皮，并且细胞内和细胞外生物胞素标记显示传入过程渗透到嵴的支持细胞层中。在3/8小鸡74传入的特点，他们显着不同于对照组（n = 130），具有较低的放电率和可忽略不计的反应，运河刺激。在中间时期有相当大的变化，在121传入的放电特性，但作为一个整体的数量的“沉默”的纤维在运河神经减少，背景率增加，并响应运河刺激检测。个别biocytin标记的传入有正常出现终端专业化的感觉上皮链霉素后28天。在后期，传入（n = 58）仍然显着不同于对照组的背景放电特性和响应增益。证据表明，相当数量的变异性存在于耳毒性损伤后前庭传入功能的恢复中，并且再生毛细胞的分泌功能可能在其换能器功能之前发挥作用。
Streptomycin sulfate (1.2 g/kg i.m.) was administered for 5 consecutive days to 5-7-day-old white Leghorn chicks; this causes damage to semicircular canal hair cells that ultimately regenerate to reform the sensory epithelium. During the recovery period, electrophysiological recordings were taken sequentially from anterior semicircular canal primary afferents using an indentation stimulus of the canal that has been shown to mimic rotational stimulation. Chicks were assigned to an early (14-18 days; n = 8), intermediate (28-34 days; n = 5), and late (38-58 days; n = 4) period based on days after treatment. Seven untreated chicks, 15-67 days old, provided control data. An absence of background and indent-induced discharge was the prominent feature of afferents in the early period: only "silent" afferents were encountered in 5/8 experiments. In several of these chicks, fascicles of afferent fibers were seen extending up to the epithelium that was void of hair cells, and intra- and extracellular biocytin labeling revealed afferent processes penetrating into the Supporting Cell layer of the crista. In 3/8 chicks 74 afferents could be characterized, and they significantly differed from controls (n = 130) by having a lower discharge rate and a negligible response to canal stimulation. In the intermediate period there was considerable variability in discharge properties of 121 afferents, but as a whole the number of "silent" fibers in the canal nerve diminished, the background rate increased, and a response to canal stimulation detected. Individually biocytin-labeled afferents had normal-appearing terminal specializations in the sensory epithelium by 28 days poststreptomycin. In the late period, afferents (n = 58) remained significantly different from controls in background discharge properties and response gain. The evidence suggests that a considerable amount of variability exists between chicks in the return of vestibular afferent function following ototoxic injury and that the secretory function of regenerating hair cells might become functional before their transducer function.