前庭毛细胞中一种新型横纹膜接触位点

文献信息

中文摘要

哺乳动物前庭系统有两种感觉受体毛细胞（HCs），每种具有不同的神经传递机制。II型HCs使用带状突触将谷氨酸等神经递质传递至传入神经元的终扣末梢。I型HCs几乎被花萼状传入末梢包裹。它们通过量子传递和非量子传递（NQT）调节传入活动，后者比经典神经递质释放更快，并且可能是快速头部运动期间稳定视觉和平衡的关键。在此，我们描述了一种新型横纹接触，仅存在于小鼠I型HC及其花萼状传入末梢中。电子断层扫描显示HC和花萼质膜上均有周期性横纹。这些接触位点与突触I型HC侧的质膜-线粒体接触位点密切相关。鉴于其他系统中线粒体-质膜接触位点调节局部离子稳态，这种独特排列有可能在I型HC-花萼突触处服务或调节NQT。

英文摘要

The mammalian vestibular system has two types of sensory receptor hair cells (HCs), each with different neurotransmission mechanisms. Type II HCs use ribbon synapses to transmit neurotransmitters like glutamate to bouton terminals of afferent neurons. Type I HCs are nearly engulfed by a calyceal afferent ending. They regulate afferent activity through both quantal and non-quantal transmission (NQT), the latter faster than classic neurotransmitter release and potentially key to stabilizing vision and balance during rapid head movements. Here, we describe a novel striated contact, present only in the mouse type I HC and its calyceal afferent ending. Electron tomography reveals periodic striations on both the HC and calyx plasma membranes. These contact sites are intimately associated with a plasma membrane mitochondria contact site on the type I HC side of the synapse. Given that mitochondrion-plasma membrane contact sites in other systems regulate local ion homeostasis, this distinctive arrangement has the potential to serve or modulate NQT at the type I HC-calyx synapse.