ELECTRON MICROPROBE ANALYSIS OF EPITHELIAL NA TRANSPORT

上皮 NA 运输的电子显微镜分析

• 批准号: 3233979
• 负责人: ROGER RICK
• 金额: $ 14.65万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-07-01 至 1991-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3233979
• 关键词: acidity /alkalinity; aldosterone; apical membrane; biological models; calcium metabolism; cell cell interaction; epithelium; homeostasis; ion transport; passive transport; saluresis; scanning electron microscopy; skin; urinary bladder

Intracellular electrolyte concentrations are determined by electron microprobe analysis to further elucidate the mechanisms underlying active transepithelial Na transport. This work, performed on isolated, well defined model epithelia like the frog skin and toad urinary bladder, may contribute to a better understanding of more complex epithelial structures, such as the mammalian kidney. The epithelia are incubated in Ussing-type chambers to monitor the functional state of transepithelial Na transport. Electron microprobe analysis is performed on thin freeze-dried cryosections in a scanning electron microscope using an energy dispersive x-ray detection system. Quantification of the intracellular electrolyte concentrations is achieved by the internal standard method. In parallel microelectrode impalements the intracellular electrical potential will be determined. The investigation will address different aspects of transepithelial Na transport in high resistance epithelia, regulation of transport, interaction between epithelial cells, and localization of transport pathways. Individual projects are designed to answer the following questions: (1) is the natriferic effect of aldosterone limited to an effect on the apical membrane and, if not, is the stimulation of the Na pump secondary to an intracellular Na increase, (2) by which mechanisms are the passive and active transport steps synchronized to maintain cellular homeostasis of ions in the face of widely varying transport rates, and (3) how do epithelial cells in a histologically complex epithelium cooperate in transepithelial transport? For this purpose the intracellular electrolyte concentrations will be determined after defined perturbations of transepithelial transport. These include the addition of stimulators and inhibitors of Na transport like aldosterone, amiloride and ouabain, procedures that affect the intracellular pH, pCa, or metabolic state, and conditions that lead to uncoupling of the cell-to-cell pathway.

细胞内电解质浓度是由电子决定的 微探针分析进一步阐明活性机制 跨上皮钠转运。这项工作在与世隔绝的油井上进行 已定义的模型上皮，如青蛙皮肤和蟾蜍膀胱，可能 有助于更好地理解更复杂的上皮结构， 比如哺乳动物的肾脏。上皮细胞在Ussing-type中孵化 监测跨上皮钠转运的功能状态。 对冷冻干燥的薄切片进行了电子探针分析。 在使用能量色散X射线的扫描电子显微镜中 探测系统。细胞内电解质的定量测定 浓度用内标法测定。并行的 微电极穿透细胞内的电势将 下定决心。调查将涉及不同方面的问题 高阻上皮细胞跨上皮钠转运的调节 转运、上皮细胞间的相互作用和细胞定位 运输通道。个别项目的设计是为了回答 以下问题：(1)醛固酮的排钠作用有限吗？ 对顶膜的影响，如果不是，则是对 钠泵继发于细胞内钠的增加，(2)其机制是什么 被动和主动运输步骤是否同步以保持 面对差异很大的传输速率时离子的细胞动态平衡， 和(3)组织学上皮中的上皮细胞是如何 在跨上皮运输方面合作？为此，细胞内 电解液浓度将在确定的扰动后确定 是跨上皮运输的。这些措施包括增加刺激剂 以及钠转运的抑制剂，如醛固酮、阿米洛利和哇巴因， 影响细胞内pH、PCA或代谢状态的程序，以及 导致细胞间通路解偶联的条件。