ELECTRON MICROPROBE ANALYSIS OF EPITHELIAL NA TRANSPORT

上皮 NA 运输的电子显微镜分析

• 批准号: 3233978
• 负责人: ROGER RICK
• 金额: $ 15.47万
• 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/3233978
• 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 微探针分析，以进一步阐明潜在的机制， 跨上皮Na转运 这项工作，在孤立的，以及 定义的模型上皮细胞，如青蛙皮肤和蟾蜍膀胱， 有助于更好地理解更复杂的上皮结构， 例如哺乳动物的肾脏。 将上皮细胞在Ussing型 室，以监测跨上皮Na转运的功能状态。 电子探针分析是在冷冻干燥的冰冻切片上进行的 在使用能量色散X射线的扫描电子显微镜中 检测系统 细胞内电解质的定量 通过内标法获得浓度。 并行 微电极穿刺，细胞内电位将 测定 调查将涉及以下不同方面： 高阻力上皮细胞跨上皮钠转运，调控 转运，上皮细胞之间的相互作用，以及 运输途径。 个别项目旨在回答 以下问题：（1）醛固酮的促钠作用是否有限 如果没有，是刺激的顶膜上的效果， Na泵继发于细胞内Na增加，（2）通过何种机制 被动和主动传输步骤是否同步， 面对广泛变化的传输速率的离子的细胞内稳态， 以及（3）在组织学上复杂的上皮中，上皮细胞如何 在跨上皮转运中合作？ 为此，细胞内 电解质浓度将在确定的扰动后确定 跨上皮转运的过程 其中包括增加刺激物 以及钠转运抑制剂，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-细胞途径解偶联的条件。