PDF(Pubmed)
Abstract：
In mammals, spatial orientation is synaptically-encoded by sensory hair cells of the vestibular labyrinth. Vestibular hair cells (VHCs) harbor synaptic ribbons at their presynaptic active zones (AZs), which play a critical role in molecular scaffolding and facilitate synaptic release and vesicular replenishment. With advancing age, the prevalence of vestibular deficits increases; yet, the underlying mechanisms are not well understood and the possible accompanying morphological changes in the VHC synapses have not yet been systematically examined. We investigated the effects of maturation and aging on the ultrastructure of the ribbon-type AZs in murine utricles using various electron microscopic techniques and combined them with confocal and super-resolution light microscopy as well as metabolic imaging up to 1 year of age. In older animals, we detected predominantly in type I VHCs the formation of floating ribbon clusters, mostly consisting of newly synthesized ribbon material. Our findings suggest that VHC ribbon-type AZs undergo dramatic structural alterations upon aging.
摘要：
在哺乳动物中,空间方向由前庭迷宫的感觉毛细胞突触编码。前庭毛细胞（VHCs）在其突触前活动区（AZs）具有突触带，在分子支架中起关键作用，促进突触释放和囊泡补充。随着年龄的增长，前庭缺陷的患病率增加；然而，潜在的机制还没有很好地理解，VHC突触中可能伴随的形态学变化尚未得到系统研究。我们使用各种电子显微镜技术研究了成熟和老化对鼠科动物带状AZs超微结构的影响，并将其与共聚焦和超分辨率光学显微镜以及长达1岁的代谢成像相结合。在老年动物中，我们主要在I型VHCs中检测到浮动带状簇的形成，主要由新合成的带状材料组成。我们的发现表明，VHC带状AZs在老化时会发生巨大的结构变化。
