Recovery of the vestibulocolic reflex after aminoglycoside ototoxicity in domestic chickens
Recovery of the vestibulocolic reflex after aminoglycoside ototoxicity in domestic chickens
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DOI：
10.1152/jn.1999.81.3.1025
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发表时间：
1999-03-01
影响因子：
2.5
通讯作者：
Rubel, EW
中科院分区：
文献类型：
--
作者：
Goode, CT;Carey, JP;Rubel, EW
鸟类的听觉和前庭毛细胞在被耳毒性药物破坏后会再生，但直到最近，几乎没有证据表明再生的前庭毛细胞功能正常。在早期的研究中，我们发现前庭眼球反射(VOR)可被氨基糖苷类抗生素治疗消除，并随着毛细胞的再生而恢复。VOR用于稳定头部的眼睛，是一个开环系统，被认为在很大程度上依赖于定期发射传入神经元。VOR的恢复与I型毛细胞的再生高度相关。相比之下，在太空中稳定头部的前庭结肠反射(VCR)是一个闭合的负反馈系统，似乎更依赖于不规则地放电传入输入，并且被认为由不同的电路而不是VOR来辅助。我们检查了毛细胞再生后，这种同样起源于前庭的不同反射是否会显示出类似的恢复。10日龄雏鸡的前庭毛细胞损伤是由5天的硫酸链霉素造成的。在链霉素治疗完成后的一天，没有可测量到的VCR增加，总毛细胞密度与未治疗的年龄匹配的对照组的35%相似。在损伤后2周，VCR显着恢复；此时，两名受试者的VCR增加在对照鸡的范围内。在损伤后3周，所有受试者的VCR增加和相移均在正常范围内。这些数据表明，VCR在VOR之前恢复。与VOR增益不同，恢复的VCR增益与再生的I型和II型前庭毛细胞密度具有同样好的相关性，但在高频情况下除外。除毛细胞再生外，其他一些因素，如静毛纤毛的长度、毛细胞的重新传入和涉及中枢神经通路的代偿，可能参与行为恢复。我们的数据表明，这些因素中的一个或多个不同地影响这两种前庭反射的恢复。
Avian auditory and vestibular hair cells regenerate after damage by ototoxic drugs, but until recently there was little evidence that regenerated vestibular hair cells function normally. In an earlier study we showed that the vestibuloocular reflex (VOR) is eliminated with aminoglycoside antibiotic treatment and recovers as hair cells regenerate. The VOR, which stabilizes the eye in the head, is an open-loop system that is thought to depend largely on regularly firing afferents. Recovery of the VOR is highly correlated with the regeneration of type I hair cells. In contrast, the vestibulocolic reflex (VCR), which stabilizes the head in space, is a closed-loop, negative-feedback system that seems to depend more on irregularly firing afferent input and is thought to be subserved by different circuitry than the VOR. We examined whether this different reflex also of vestibular origin would show similar recovery after hair cell regeneration. Lesions of the vestibular hair cells of 10-day-old chicks were created by a 5-day course of streptomycin sulfate. One day after completion of streptomycin treatment there was no measurable VCR gain, and total hair cell density was similar to 35% of that in untreated, age-matched controls. At 2 wk postlesion there was significant recovery of the VCR; at this time two subjects showed VCR gains within the range of control chicks. At 3 wk postlesion all subjects showed VCR gains and phase shifts within the normal range. These data show that the VCR recovers before the VOR. Unlike VOR gain, recovering VCR gain correlates equally well with the density of regenerating type I and type II vestibular hair cells, except at high frequencies. Several factors other than hair cell regeneration, such as length of stereocilia, reafferentation of hair cells, and compensation involving central neural pathways, may be involved in behavioral recovery. Our data suggest that one or more of these factors differentially affect the recovery of these two vestibular reflexes.