Developmental segregation in the efferent projections to auditory hair cells in the gerbil.
Developmental segregation in the efferent projections to auditory hair cells in the gerbil.
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沙鼠听觉毛细胞传出投射的发育分离。
DOI：
10.1002/cne.10931
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
Echteler,StephenM
中科院分区：
文献类型：
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作者：
Rontal,DanielA;Echteler,StephenM
哺乳动物的听觉感受器上皮接受来自脑干的上级橄榄复合体内和周围的神经元的传出神经支配（Warr [1975] J.Comp.Neurol. 161：159-181）。在出生后早期，当橄榄耳蜗轴突与听觉毛细胞和神经纤维形成其最终连接时，该通路的中断可导致严重和永久性的听力损伤（沃尔什等人，2005）。[1998] J. Neurosci. 18：3859-3869）。识别这种听觉功能恶化的可能原因需要更好地了解耳蜗内传出轴突及其靶细胞之间发生的正常发育相互作用。为了提供这样的信息，我们使用荧光碳菁染料1，1-双十八烷基-3，3，3，3-四甲基吲哚碳菁高氯酸盐（DiI）标记在沙鼠耳蜗内恒定位置的传出纤维。这些神经元的终末乔木，然后通过使用数字共聚焦显微镜重建。到出生后第2天（P），与内毛细胞（IHC）和外毛细胞（OHC）相关的传出动脉显示出明显不同的形态，与成年动物所描述的形态非常相似（Brown [1987] J. Comp. Neurol. 260：605-619）。然而，与它们的成熟对应物不同，P2传出轴突经常分支以接触两种类型的听毛细胞。出乎意料的是，在P4和P6之间，IHC和OHC传出轴突都产生了额外的分支，这些分支穿过Corti隧道侵入OHC区。到了P8，所有这些多余的连接都被消除，产生了完全分离的IHC和OHC的传出通路。神经学比较杂志© 2003 Wiley-Liss，Inc.
The auditory receptor epithelium of mammals receives efferent innervation from neurons within and surrounding the superior olivary complex of the brainstem (Warr [1975] J. Comp. Neurol. 161: 159–181). Disruption of this pathway during early postnatal life, when olivocochlear axons are forming their final connections with auditory hair cells and nerve fibers, can lead to profound and permanent hearing impairments (Walsh et al.[1998] J. Neurosci. 18: 3859–3869). Identification of the possible causes for this deterioration in auditory function requires a better understanding of the normal developmental interactions that occur between efferent axons and their target cells within the cochlea. To provide such information, we labeled developing efferent fibers at a constant location within the gerbil cochlea by using the fluorescent carbocyanine dye 1, 1-dioctadecyl-3, 3, 3, 3-tetramethylindocarbocyanine perchlorate (DiI). The terminal arbors of these neurons were then reconstructed by using digital confocal microscopy. By postnatal day (P) 2, the efferent arbors associated with inner hair cells (IHCs) and outer hair cells (OHCs) displayed distinctly different morphologies closely resembling those described for adult animals (Brown [1987] J. Comp. Neurol. 260: 605–619). Unlike their mature counterparts, however, P2 efferent axons frequently branched to contact both types of auditory hair cells. Unexpectedly, between P4 and P6, both IHC and OHC efferent axons produced additional branches that crossed the tunnel of Corti to invade the OHC zone. By P8, all of these supernumerary connections were eliminated, yielding completely segregated efferent pathways to IHCs and OHCs. J. Comp. Neurol. 467: 509–520, 2003.© 2003 Wiley-Liss, Inc.