PHYSIOLOGY OF RETINAL MULLER CELLS AND ASTROCYTES

视网膜米勒细胞和星形胶质细胞的生理学

• 批准号: 2391661
• 负责人: ERIC A NEWMAN
• 金额: $ 27.81万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 2000-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2391661
• 关键词: Muller's cell; Urodela; acid base balance; acidity /alkalinity; adenosinetriphosphatase; antiport; astrocytes; carbonates; confocal scanning microscopy; electroretinography; glia; laboratory rat; membrane potentials; membrane transport proteins; retina; vitreous body; voltage /patch clamp

The long term objectives of this research are to characterize the membrane properties of Muller cells and retinal astrocytes and to relate these properties to possible glial cell functions in the retina, including the regulation of extracellular pH and [K]o, the control of retinal blood flow, and the generation of the electroretinogram. Specific aims for the project period differ from previous periods and examine, primarily, pH regulation in retinal glial cells. The aims are; (1) Characterize the acid/base transport systems of amphibian and mammalian Muller cells. Hypotheses to be tested include; (i) Muller cells possess an electrogenic Na+/HCO-3 cotransport system and a Cl-/HCO-3 exchanger which are both localized tot he cell endfoot. (ii) Muller cells possess a Na+/H+ exchanger and a H+-ATPase. (2) Test the hypothesis that muller cells modulate extracellular pH (pHo) by the action of the electrogenic Na+/HCO-3 cotransporter. The hypothesis will be tested in two preparations; (i) dissociated Muller cells (Salamander and rat) and (ii) Muller cells in situ in the isolated rat retina. (3) Test the hypothesis that Muller cells regulate pHo in the retina by functioning as CO2 buffers, transporting CO2, in the form of H- and HCO-3, to the vitreous humor. (4) Characterize the acid/base transport systems of mammalian astrocytes in situ. Specific hypotheses to be tested include: (i) the acid/base transport systems of mammalian astroytes in situ have properties similar to those found in Muller cells and cultured astrocytes. (ii) the Na+/HCO-3 cotransport system of mammalian astrocytes in situ is localized in cell endfeet. (5) Test the hypothesis that glial cells regulate blood flow in the mammalian retina. Blood vessel diameter will be monitored in the isolated rat retina as the membrane potential of glial cells is modulated by current injection. Acid/base transport systems will be characterized by monitoring intracellular and extracellular pH with ratio imaging of pH-sensitive indicator eyes. Measurements in dissociated salamander and rat muller cells will be made by imaging the dye BCECF with inverted fluorescence microscopy. In situ measurements in the isolated rat retina will be made by confocal imaging of the dye SNARF-1. Elucidating the basic membrane properties of Muller cells and retinal astrocytes is necessary for understanding the ole that these cells play in retinal function under normal and pathological condiitons, including retinitis pigmentosa and macular dystrophy.

这项研究的长期目标是表征膜 Muller细胞和视网膜星形胶质细胞的特性，并将其关联 视网膜中可能的神经胶质细胞功能的特性，包括 调节细胞外pH和[k] o，视网膜血流的控制， 以及电子图的产生。 该项目的具体目标 周期与以前的时期不同，主要检查pH调节 在视网膜神经胶质细胞中。 目的是； （1）表征 两栖动物和哺乳动物的穆勒细胞。 要测试的假设包括； （我） Muller细胞具有电源NA+/HCO-3共转运系统和A Cl-/hco-3交换器都是局部的细胞端脚。 （ii） Muller细胞具有Na+/H+交换器和H+-ATPase。 （2）测试 假设Muller细胞通过作用调节细胞外pH（PHO） 电源Na+/HCO-3共转运蛋白。 该假设将进行检验 在两次准备工作中； （i）解离的穆勒细胞（sal和大鼠）和 （ii）在分离的大鼠视网膜中原位的穆勒细胞。 （3）测试 假设Muller细胞通过作用为视网膜中的Pho 二氧化碳缓冲液以H-和HCO-3的形式运输CO2到玻璃体 幽默。 （4）表征哺乳动物的酸/碱基运输系统 当地星形胶质细胞。 要测试的特定假设包括：（i） 哺乳动物Astroytes原位具有特性的酸/碱基运输系统 与在穆勒细胞和培养的星形胶质细胞中发现的类似。 （ii） NA+/HCO-3哺乳动物星形胶质细胞原位的共转运系统已局部 在小区终端中。 （5）测试神经胶质细胞调节血液的假设 哺乳动物视网膜中的流动。 血管直径将被监测 分离的大鼠视网膜作为神经胶质细胞的膜电位为 通过当前注入调节。 酸/基本运输系统将通过监测来表征 细胞内和细胞外pH，pH敏感的比率成像 指示灯。 分解的Salamander和Rat Muller的测量 将通过倒荧光成像染料BCECF来制作细胞 显微镜。 将进行孤立的大鼠视网膜的原位测量 通过染料SNARF-1的共聚焦成像。 阐明穆勒细胞和视网膜的基本膜特性 星形胶质细胞对于理解这些细胞发挥作用的OLE是必需的 在正常和病理对照室下的视网膜功能，包括 色素性视网膜炎和黄斑营养不良。