THE MECHANISM OF OUTER HAIR CELL MOTILITY

描述：(改编自《调查者摘要》)外毛细胞 哺乳动物耳蜗的感觉感受器细胞(OHC)在 是电刺激的。在体内由声感受器驱动的OHC力 电势，被认为贡献了额外的一步机械激励( “耳蜗放大器”)，改善调谐，容易受到疾病和 侮辱。这个实验室最近的实验表明，轴向 OHC的刚度是将OHC电压依赖电机连接到 它的负载，科尔蒂的器官。但对OHC的僵硬程度一无所知 相关的声频也不是OHC背后的蜂窝组件 僵硬理解。这项提案有三个具体目标，将提供 这些信息。在AIM1中，将直接测量OHC阻抗(刚度 使用一种新的仪器--激光拉伸器。是否 膜电位调制阻抗--一种已提出的耳蜗学机制 放大器-将进行测试。第一次直接测量等轴向力将 被创造出来。在目标2中，OHC僵硬在听力发育中的作用将 被确定，特别是OHC僵硬的开始是否是一个限制 耳蜗放大器发展中的事件。在目标3中， 皮质，OHC中的一种亚细胞结构将使用 发展方法。

DESCRIPTION: (Adapted from the Investigator's Abstract) The outer hair cell (OHC) of the mammalian cochlea, a sensory receptor cell, generates force when electrically stimulated. OHC force, driven in vivo by the acoustic receptor potential, is thought to contribute an extra step of mechanical excitation (the "cochlear amplifier") that improves tuning and is vulnerable to disease and insult. Recent experiments in this laboratory have shown that the axial stiffness of the OHC is essential to connect the OHC voltage-dependent motor to its load, the organ of Corti. But nothing is known about OHC stiffness at relevant acoustic frequencies nor are the cellular components underlying OHC stiffness understood. This proposal has three specific aims that will provide this information. In Aim1, OHC impedance (stiffness) will be measured directly at acoustic frequencies using a novel instrument, the laser stretcher. Whether membrane potential modulates impedance-a proposed mechanism of the cochlear amplifier-will be tested. The first direct measurement of isometric force will be made. In Aim 2, the role of OHC stiffness in the development of hearing will be determined, specifically whether the onset of OHC stiffness is a limiting event in development of the cochlear amplifer. In Aim 3, the role of the cortex, a subcellular structure in OHC stiffness will be determined using a developmental approach.