THE MECHANISM OF OUTER HAIR CELL MOTILITY

描述：（改编自研究者摘要）外毛细胞 哺乳动物耳蜗的（OHC）是一种感觉受体细胞，当 电刺激。 OHC 力，由声感受器在体内驱动 潜力，被认为有助于机械激发的额外一步（ “耳蜗放大器”）可以改善调谐，并且容易感染疾病和 侮辱。该实验室最近的实验表明，轴向 OHC 的刚度对于将 OHC 电压相关电机连接到 它的负载，柯蒂氏器官。但对于 OHC 刚度一无所知 OHC 的相关声学频率和细胞成分都不是 刚度理解。该提案具有三个具体目标 这些信息。在 Aim1 中，将直接测量 OHC 阻抗（刚度） 使用一种新颖的仪器，即激光担架，以声波频率进行测量。是否 膜电位调节阻抗——一种提出的耳蜗机制 放大器将被测试。等长力的首次直接测量将 被制作。在目标 2 中，OHC 硬度在听力发展中的作用将 确定，特别是 OHC 僵硬的发生是否是一个限制 耳蜗放大器开发过程中的事件。在目标 3 中， 皮质，OHC 硬度的亚细胞结构将使用 发展方式。

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.