PHARMACOLOGICAL ANALYSIS OF IONIC BALANCE IN HAIR CELLS

毛细胞离子平衡的药理学分析

• 批准号: 2124190
• 负责人: EDMUND A MROZ
• 金额: $ 21.64万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-04-01 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2124190
• 关键词: acidity /alkalinity; active transport; amiloride; bicarbonates; calcium channel; calcium flux; calcium transporting ATPase; cell morphology; chloride channels; ear hair cell; ear pharmacology; electrolyte balance; electron probe spectrometry; fluorimetry; goldfish; guinea pigs; inhibitor /antagonist; ion transport; magnesium; membrane potentials; membrane transport proteins; neuropharmacology; phosphorus; sodium potassium exchanging ATPase; tissue /cell culture

The proper functioning of hair cells, the sensory transducing cells of the auditory and vestibular systems, depends on proper ionic compositions both outside and inside those cells. The nature of some insults to hair cells and of the resulting injuries suggest that pathophysiological changes to hair cells can involve loss of proper ionic balance (e.g., in temporary threshold shifts, acoustic trauma, ototoxicity, Meniere's disease, and aging). Loss of ionic balance would prevent normal hair cell function, and could lead to permanent damage, if for example, the hair cell consequently lose the ability to regulate cell volume. Since damage to hair cells is a frequent cause of deafness, understanding the ionic balance processes of hair cell may eventually help to prevent or minimize some forms of hearing loss. The long-term objective of this project is to determine how hair cells regulate their intracellular ionic state. This information will fill a major gap in knowledge about the normal physiology of hair cells and will eventually help to evaluate whether loss of ionic balance plays a role in pathophysiology. The experimental approach is to subject isolated hair cells to treatments designed to affect specific cellular mechanism that influence ion balance. Electron-probe microanalysis is then used to determine ion composition and net ion-transport rates of hair cells. This method allows quantitative stud of electrically silent transporters and active ion pumps that are hard to study with other techniques. Quantitative microfluorometry of ion-specific dyes will provide further information about intracellular binding or sequestration of ions once they have entered the hair cells. Cell volume will be measured with quantitative video microscopy. Changes in membrane potential will be determined. Work during the next project period will address fundamental questions about the individual ion-transport processes whose dynamic interactions establish ion balance in the cell. Experiments will examine how flows of sodium, potassium, chloride, calcium, an d hydrogen ion, through each of their major pathways across the hair-cell membrane, depend on ion concentration inside and outside the cell, on the energy sources that power ion transport, and on the membrane potential. The effects of these experiments on the intracellular handling of calcium and hydrogen ions will be determined. Since we will measure all the major permanent cell ions in these experiments, we will also be able to discover unexpected interactions among the individual ion-balance processes. In addition to their importance for understanding basic hair-cell physiology, these studies will forming a solid technical and intellectual basis for future work to evaluate the role of alterations of hair-cell ion balance in different forms of hearing loss.

毛细胞的正常功能，感觉传导细胞 听觉和前庭系统，取决于适当的离子成分 无论是在这些牢房的外面还是里面。一些对头发的侮辱的性质 细胞和由此造成的损伤表明，病理生理 毛细胞的变化可能涉及失去适当的离子平衡(例如，在 暂时性阈值漂移、声损伤、耳毒性、梅尼埃氏症 疾病和衰老)。离子平衡的丧失会妨碍正常的毛细胞 功能，并可能导致永久性损害，例如，头发 因此，细胞失去了调节细胞体积的能力。自损坏以来 毛细胞是耳聋的常见原因，了解离子 毛细胞的平衡过程最终可能有助于防止或最小化 某些形式的听力损失。 这个项目的长期目标是确定毛细胞如何 调节它们的细胞内离子状态。此信息将填充 在毛细胞的正常生理和意志方面的主要知识差距 最终有助于评估离子平衡的丧失是否起到了作用 在病理生理学方面。 实验方法是对分离的毛细胞进行处理。 旨在影响影响离子的特定细胞机制 平衡。然后使用电子探针微量分析来确定离子 毛细胞的组成和净离子转运率。这种方法 允许对电子静默转运体和活动转运体进行定量研究 用其他技术很难研究的离子泵。量化 离子特定染料的显微荧光测量将提供进一步的信息 关于离子一旦有了细胞内的结合或隔离 进入毛细胞。细胞体积将用定量的 视频显微镜。膜电位的变化将被测定。 下一个项目期间的工作将解决基本问题 关于单个离子输运过程的动力学相互作用 在细胞内建立离子平衡。实验将检验流动是如何 钠、钾、氯、钙和氢离子，通过每一个 它们穿过毛细胞膜的主要途径中，依赖于离子 专注于细胞内外的能量来源， 功率离子的传输，以及对膜电位的影响。这些因素的影响 细胞内处理钙离子和氢离子的实验研究 将会被确定。因为我们将测量所有主要的永久细胞 在这些离子实验中，我们还将能够发现意想不到的 各个离子平衡过程之间的相互作用。除了……之外 它们对于理解基本毛细胞生理学的重要性 研究将为未来奠定坚实的技术和智力基础 评估毛细胞离子平衡改变在疾病中的作用 不同形式的听力损失。