TRANSDUCTION MECHANISM OF VERTEBRATE HAIR CELLS

脊椎动物毛细胞的转导机制

• 批准号: 3400764
• 负责人: ALBERT JAMES HUDSPETH
• 金额: $ 14.98万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-07-01 至 1987-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3400764
• 关键词: aminoglycoside antibiotics; antibiotics; auditory stimulus; autoradiography; cochlear microphonic potentials; ear hair cell; ear pharmacology; electrical potential; electrolyte balance; electron microscopy; fresh water environment; hearing; labyrinth; mechanoreceptors; membrane permeability; neural transmission; neuroanatomy; ototoxin; single cell analysis; vibration perception

The least understood process of the inner ear, the transduction of mechanical stimuli into electrical responses, is also the stage at which severe pathology of the auditory and vestibular systems most often arises. We propose to employ the techniques of cell biology and membrane biophysics to investigate how transduction normally operates and how it is affected by a clinically important class of ototoxic agents, the aminoglycoside antibiotics. These studies will contribute to an understanding of transduction which, in the long term, will aid in the rational design of prophylaxis or treatment for conditions such as aminoglycoside ototoxicity, acoustic trauma, presbyacusis, and Meniere's disease. Hair cells from the bullfrog's inner ear will be maintained in vitro either within the saccular epithelium or as solitary cells dissociated by enzymes. The relationship between deflection of a cell's mechanosensitive hair bundle and the resultant receptor potential and membrane conductance changes will be carefully studied with stimuli of a variety of frequencies, amplitudes, and waveforms. The results will be of value in modeling the operation of less accessible organs such as the mammalian cochlea and vestibular apparatus. The subcellular site at which transduction occurs will be sought both by measuring the pattern of current flow around the hair bundle and by localizing the influx of calcium ion through activated transduction channels. The permeability of the transducer's ionic channel will be plumbed with radioactive tris(hydroxymethyl) aminomethane, an ion whose intracellular accumulation may also serve to label stimulated hair cells. As a step toward elucidation of the mechanism whereby aminoglycoside antibiotics damage hair cells, the site of action and binding kinetics of these drugs will be determined. It should be possible to learn whether ototoxic antibiotics interfere with cellular metabolism or exert their effects upon binding to a membrane receptor. Voltage-clamp experiments will be performed on isolated hair cells in order to estimate the conductance of individual transduction channels and to identify other membrane conductance mechanisms that affect the form of the receptor potential.

内耳最不为人所知的过程， 机械刺激转化为电反应，也是一个阶段， 听觉和前庭系统的严重病变最经常出现。 我们建议采用细胞生物学和膜生物物理学技术 研究转导如何正常运作，以及它如何受到 一种临床上重要的耳毒性药物，氨基糖苷类 抗生素 这些研究将有助于了解 从长远来看，这将有助于合理设计 预防或治疗诸如氨基糖苷类耳毒性的病症， 听觉创伤、老年性聋和梅尼埃病。 毛细胞来自 牛蛙的内耳将保持在体外， 上皮细胞或由酶解离的孤立细胞。 的关系 细胞的机械敏感毛束的偏转和 由此产生的受体电位和膜电导的变化将是 仔细研究了各种频率、振幅和 波形 其结果将在建模少的操作的价值 哺乳动物的耳蜗和前庭器官等可接近的器官。 转导发生的亚细胞位点将通过以下两种方法来寻找： 测量围绕所述发束的电流模式， 通过激活转导定位钙离子内流 渠道 换能器离子通道的渗透性将是 放射性三（羟甲基）氨基甲烷，一种离子， 细胞内积累也可用于标记受刺激的毛细胞。 作为阐明氨基糖苷类药物 抗生素损伤毛细胞，作用部位和结合动力学 这些药物将被确定。 应该可以了解到 耳毒性抗生素干扰细胞代谢或发挥其 对膜受体结合的影响。 电压钳实验 将在分离的毛细胞上进行，以估计 个别转导通道的电导，并确定其他 影响受体形式的膜传导机制 潜力