METABOLIC AND HOMEOSTATIC MECHANISMS IN RETINA AND RPE

视网膜和 RPE 的代谢和稳态机制

• 批准号: 6518496
• 负责人: BARRY S. WINKLER
• 金额: $ 33.07万
• 依托单位: OAKLAND UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6518496
• 关键词: Krebs' cycle; Muller's cell; aspartate transaminase; bioenergetics; carbon dioxide; electrophysiology; gamma aminobutyrate; glutamates; glutamine; guinea pigs; homeostasis; ion transport; laboratory rat; mitochondria; phosphorylation; retina; retina detachment; retinal pigment epithelium; visual photoreceptor

DESCRIPTION (Adapted from the applicant's abstract): There are two long-range goals in this renewal application. The first goal is to understand the mechanism by which various classes of cells in mammalian retina obtain energy. The classical view is that glucose is the primary substrate for retinal energy metabolism and that photoreceptor cells have the highest metabolic rates. A different and more recent view (termed "metabolic trafficking") is that Muller cells are the principal, if not sole, producers of lactate, which then serves as the primary fuel for the mitochondria in photoreceptor cells and retinal neurons. A third preferred substrate, glutamate, initially metabolized by the enzyme aspartate aminotransferase (AAT), has also been proposed. The following specific aims will evaluate these contrasting hypotheses of retinal metabolism. The cellular sites of glucose uptake and phosphorylation will be identified in studies with labeled 2-deoxyglucose. Mitochondrial production of carbon dioxide will be measured with labeled glucose, glutamate, or lactate with and without inhibitors of AAT in order to establish the metabolic priority of substrates utilized by rat and guinea pig retinal mitochondria and the role of AAT in regulating the rate of the Krebs cycle activity. In addition, the specific contribution of Muller cells to glycolysis and respiration in whole retinas will be evaluated by using gliotoxins to selectively kill these cells in rat and guinea pig retinas: cell morphology and activity of glutamine synthetase will be used as markers of toxicity. These experiments will provide new and important information regarding the three competing hypotheses for retinal energy metabolism and provide a basis for a better understanding of the vulnerability of specific retinal ischemia. The second goal expands on these studies of retinal metabolism to understand roles played by ion transport and metabolic trafficking across the RPE in photoreceptor function and retinal adhesion. The proposed experiments were developed following the striking observation that incubation of rat eyecups in bicarbonate-free medium quickly leads to retinal detachment. Experiments will also examine retinal re-attachment by restoration of bicarbonate to the bathing medium or the addition of certain drugs (e.g., diamox) which have been reported to decrease retinal edema. A long-term goal of the second project is to understand better the nature of the interactions between the retina and RPE and factors regulating retinal detachment.

描述（改编自申请人的摘要）：有两个远程 此续订应用程序中的目标。第一个目标是了解 哺乳动物视网膜中各种细胞获得能量的机制。 经典的观点是，葡萄糖是视网膜能量的主要底物 代谢和感光细胞的代谢率最高。一个 穆勒（Muller） 细胞是主要的，即使不是唯一的乳酸生产者，然后才能使用 作为光感受器细胞和视网膜中线粒体的主要燃料 神经元。第三个首选底物，谷氨酸，最初由 还提出了酶天冬氨酸氨基转移酶（AAT）。下列 具体目标将评估视网膜代谢的这些对比假设。 在 标记为2-脱氧葡萄糖的研究。二氧化碳的线粒体生产 将用标记的葡萄糖，谷氨酸或乳酸来测量 AAT的抑制剂以建立底物的代谢优先级 由大鼠和豚鼠视网膜线粒体和AAT在 调节克雷布斯循环活性的速率。另外，具体 穆勒细胞对整个视网膜中糖酵解和呼吸的贡献 将通过使用Gliotoxins选择性杀死这些细胞在大鼠中评估 和豚鼠视网膜：谷氨酰胺合成酶的细胞形态和活性 将用作毒性标记。这些实验将提供新的和 有关视网膜的三个竞争假设的重要信息 能源代谢，并为更好地理解 特定视网膜缺血的脆弱性。第二个目标扩大了这些 研究视网膜代谢的研究，以了解离子运输和 在光感受器功能和视网膜中，跨RPE的代谢运输 粘附。提出的实验是在罢工之后开发的 观察到，迅速在无碳酸氢盐培养基中孵育大鼠眼睛。 导致视网膜脱离。实验还将检查视网膜 通过将碳酸氢盐恢复到沐浴介质或 据报道添加某些药物（例如Diamox） 视网膜水肿。第二个项目的长期目标是更好地了解 视网膜和RPE之间相互作用的性质与因素 调节视网膜脱离。