The mechanical and ionic roles of cochlear fluids in hearing and hearing loss

项目摘要 耳蜗生理学实验室的一个目标是了解Corti器官的组件如何调整 声音引起的科尔蒂器官的振动。一种被称为耳蜗放大(CA)的过程，现在的主题是 在世界各地的紧张工作中，有一些关键部件尚未被研究。两个广受关注的问题 本提案的主要内容是：1)基本流体动力粘性如何对 处理语音频率的耳蜗尖的频率分析能力和2)执行 被膜在调节钙离子浓度方面起着中心的生化作用。 对毛细胞功能至关重要。有三个目标。 需要新的和创新的实验方法来解决这些问题。用于测量 输出变量，我们继续使用我们首创的光学相干层析成像(OCT)方法 记录内耳组织振动。我们使用最先进的共焦成像方法应用于整个器官 外植体系统，并测量静止和刺激内耳中的钙离子浓度。 在目标1中，关于问题1，我们还建议确定外淋巴宏观粘度是否是至关重要的 心尖频率调谐的参数。以及调谐是否依赖于耳蜗的过程 行波传播到顶点时，行波内部的放大。操控粘度，正常外淋巴 通过实时灌流系统被改变粘度的外淋巴取代。目标2和目标3与问题2有关 在这里，我们试图了解钙是如何被覆盖膜储存的，以及由此产生什么后果。 所涉及的是利用突变壁画模型对有缺陷的覆盖膜结构蛋白和定量 内淋巴和覆盖膜中钙离子浓度的荧光测定。此外，在AIM中 3，我们通过两个模型探讨了年龄是如何影响被膜钙隔离的。 操纵血管纹的生理学，这是已知的年龄退化的目标。模式1是慢性病 速尿抑制耳蜗内电位的应用。模式2是基因靶向的 血管纹血流的化学改变)。综上所述，这项工作不仅将大大推进 对Corti器官功能的基础知识，但为药物干预治疗开辟了一条道路 覆膜钙化病理。

Project Summary A goal of the cochlear physiology laboratory is to understand how the components of the organ of Corti tune the sound induced vibration of the organ of Corti. A process known as cochlear amplification (CA), now the subject of intense work around the world, has critical components not yet studied. Two questions of broad interest that this proposal address are; 1) how does the fundamental hydrodynamic viscosity contribute to the unique frequency analysis capacity of the cochlear apex where speech frequencies are processed and 2) does the tectorial membrane in have a central and biochemical role in regulating the calcium ion concentration that is so critical to hair cell function. There are three Aims. New and innovative experimental approaches are needed to address these questions. For the measurement of output variables, we continue to use the optical coherence tomography (OCT) method, that we pioneered, to record inner ear tissue vibration. We use state of the art confocal imaging methods applied to whole organ explant systems and measure calcium ion concentrations in quiescent and stimulated inner ears. In Aim 1, about question 1, we also propose to determine if perilymph macroscopic viscosity is a crucial parameter of apical frequency tuning. As well as whether the tuning is dependent upon the process of cochlear amplification within the traveling wave as it propagates to the apex. To manipulate viscosity, normal perilymph is replaced with altered viscosity perilymph via a real time perfusion system. Aims 2 and 3 are about question 2 where we seek to understand how and with what consequence is calcium stored by the tectorial membrane. Involved is the use of mutant mural models of defective tectorial membrane structural proteins and quantitative fluorescent determination of calcium concentrations in endolymph and tectorial membrane. Additionally, in Aim 3, we explore how age might factor into the tectorial membrane calcium sequestration via two models that manipulate the physiology of the stria vascularis a known target of age degeneration. Model 1 is the chronic application of furosemide, an agent to suppress endocochlear potential. Model 2 is the genetically targeted chemical alteration of stria vascularis blood flow). Taken together the work will significantly advance not only fundamental knowledge of organ of Corti function but open a path to pharmacological interventions to treat tectorial membrane calcium pathology.