THE MECHANISM OF OUTER HAIR CELL MOTILITY

描述：（改编自研究者摘要）外毛细胞 (OHC)哺乳动物耳蜗的感觉感受器细胞，当 电刺激。OHC力，由声感受器在体内驱动 潜在的，被认为有助于机械激励的额外步骤（ “耳蜗放大器”），改善调谐和易受疾病和 侮辱。该实验室最近的实验表明， OHC的刚度对于将OHC电压依赖型电机连接到 它的负载，Corti的器官。但是对于OHC刚度， 相关的声频也不是OHC的细胞成分 理解的僵硬。该提案有三个具体目标， 的该项目海外在Aim 1中，将直接测量OHC阻抗（刚度 使用一种新的仪器，激光展宽器。是否 膜电位调节阻抗-耳蜗的一种拟议机制 将被测试。第一次直接测量等长力将 被制造。在目标2中，OHC刚度在听力发展中的作用将 确定，特别是OHC刚度的开始是否是一个限制 耳蜗放大器发展中的一个事件。在目标3中， 皮质，OHC硬度的亚细胞结构将使用 发展的方法。

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.