ULTRASTRUCTURE OF AFFERENT INNERVATION AT INNER HAIR CELLS IN MOUSE

小鼠内毛细胞传入神经支配的超微结构

• 批准号: 7358095
• 负责人: Howard W Francis
• 金额: $ 1.02万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7358095
• 关键词: ULTRASTRUCTURE; AFFERENT; INNERVATION; INNER; HAIR

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The structure and underlying physiology of afferent innervation in the mammalian cochlea is only partially understood in cat and is essentially unknown in mouse. The increasing importance of mouse as an animal model in hearing research necessitates a more detailed analysis of the critical synaptic interface between the inner hair cell (IHC), the transducer of sound, and auditory nerve fibers. Dr. Francis¿ preliminary studies of afferent terminal and synaptic ultrastructure at this interface in the C57BL/6J mouse have revealed two morphologically distinct groups of afferent endings. One of these endings is a conventional bouton, whereas the other has novel morphological features including the presence of a deep sulcus apparently created by the invagination of the outer membrane. This ending has been called the folded ending and accounts for about a half of the terminals that form afferent synapses with IHCs at 8, 16 and 32 kHz sites. This morphology has been observed in 3 out of 4 C57BL/6J mice studied so far. Dr. Francis proposes a study in which electron tomography is used to elucidate the 3-dimensional structure of the sulcus in folded terminals and particularly its relationship to the outer membrane of the nerve terminal. The sulcus partially compartmentalizes the terminal and appears to sequester mitochondria and other organelles. Electron tomography would be helpful in showing these complex relationships, which may provide insight into the functional role of this unusual structure. Dr. Francis also proposes to examine the spatial relationships between components of the afferent synapse including the pre-synaptic body, and vesicles bound to both the pre-synaptic membrane and ribbon. This study will provide valuable information about the synaptic machinery (especially the releasable pool of vesicles) and would find immediate use in on-going studies of afferent synaptic transmission in this animal.

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。哺乳动物耳蜗内传入神经的结构和基本生理在猫中只有部分了解，在小鼠中基本上是未知的。小鼠在听力研究中作为动物模型的重要性日益增加，因此有必要对内毛细胞(IHC)、声音传导者和听神经纤维之间的关键突触界面进行更详细的分析。Francis博士对C57BL/6J小鼠这一界面的传入终末和突触超微结构的初步研究揭示了两组在形态上不同的传入末梢。其中一个是传统的末端，而另一个具有新奇的形态特征，包括明显由外膜内陷造成的深沟的存在。这种末端被称为折叠末端，约占在8、16和32 kHz处与IHC形成传入突触的终末的一半。到目前为止，在所研究的4只C57BL/6J小鼠中，有3只观察到了这种形态。弗朗西斯博士提出了一项研究，利用电子断层扫描来阐明折叠终末沟的三维结构，特别是它与神经末梢外膜的关系。沟将终末部分隔开，似乎隔离了线粒体和其他细胞器。电子断层扫描将有助于显示这些复杂的关系，这可能提供洞察这种不寻常的结构的功能作用。弗朗西斯博士还建议研究传入突触的组成部分之间的空间关系，包括突触前小体，以及与突触前膜和突触带结合的小泡。这项研究将提供有关突触机制(特别是可释放的囊泡池)的有价值的信息，并将立即用于正在进行的该动物传入突触传递的研究中。