Spatially resolved measurements of retinal metabolism

摘要 详细了解视网膜新陈代谢是了解视网膜如何承受、补偿 因为或遭受系统变化和疾病带来的压力。此应用程序采用新的 通过空间记录了解哺乳动物视网膜的糖酵解和氧化代谢的方法 用数学方法研究大鼠和小鼠视网膜微电极氧和pH的变化 扩散模型，以提取有关基质利用率和废物产生的信息，以及 使用药理学来分离不同的过程。这一策略是对以前在体内和 体外方法，但允许分离视网膜内外的代谢事件，这是很少的 这是可能的，但不能通过测量整个组织的新陈代谢来完成。微电极 方法允许同时记录经视网膜和视网膜内视网膜电信号以监测视网膜 功能。有三个目标。1)将记录氧气的深度剖面，以便定量确定 离体视网膜的新陈代谢与体内的相比如何，内部和外部的视网膜有何不同？ 在新陈代谢方面。众所周知，光感受器可以进行高速率的(无氧)糖酵解，但平衡 在视网膜内部，氧化和糖酵解之间的能量产生尚不清楚，以及这种变化是否会发生 这取决于葡萄糖的供应。视网膜血流量对闪烁的光(神经血管)的反应增加 耦合)，但驱动这一变化的内部视网膜新陈代谢变化的大小尚不清楚，而且将是 在这里测量。2)通过记录分离视网膜中pH的深度分布，酸性废物的产生将被 量化的。糖酵解和氧化代谢在产酸方面有很大的不同。要确定 产酸、缺氧和抑制糖酵解或氧化的代谢毒药的成分 将使用新陈代谢。3)在一些组织中，有证据表明糖酵解和氧化代谢 分隔化，乳酸和/或丙酮酸从糖酵解活性细胞转移到 更多地依赖于氧化代谢。这一概念导致了视网膜使用类似策略的想法， 乳酸盐在米勒细胞中产生，并穿梭到神经元。相对较新的可用 单羧酸盐转运的选择性阻滞剂提供了一个评估这种 在内视网膜和外视网膜都有定量的转移。所有要获得的信息都是 了解视网膜在疾病中如何变化，以及视网膜内外的功能是什么 不同条件下的氧化代谢和糖酵解代谢。

Abstract Understanding retinal metabolism in detail is fundamental to knowing how the retina withstands, compensates for, or suffers from the stresses imposed by systemic changes and disease. This application takes a new approach to understanding glycolytic and oxidative metabolism of the mammalian retina, by recording spatial profiles of oxygen and pH in the isolated rat and mouse retina with microelectrodes, using mathematical models of diffusion to extract information about rates of substrate utilization and waste generation, and employing pharmacology to isolate different processes. This strategy is complimentary to previous in vivo and in vitro approaches, but allows a separation of metabolic events in the inner and outer retina, which has rarely been possible, and cannot be done with measurements of whole tissue metabolism. Microelectrode approaches simultaneously allow recording of transretinal and intraretinal electroretinograms to monitor retinal function. There are three aims. 1) Depth profiles of oxygen will be recorded in order to determine quantitatively how the metabolism of the isolated retina compares to that in vivo, and how the inner and outer retina differ metabolically. Photoreceptors are known to perform high rates of (anaerobic) glycolysis, but the balance between oxidative and glycolytic energy production is not known in the inner retina, and whether this changes depending on glucose supply. Retinal blood flow increases in response to flickering light (neurovascular coupling), but the size of the metabolic change in the inner retina that drives this is unknown, and will be measured here. 2) By recording depth profiles of pH in the isolated retina, the production of acidic waste will be quantified. Glycolysis and oxidative metabolism are very different in acid production. To identify the components of acid production, hypoxia and metabolic poisons that suppress either glycolysis or oxidative metabolism will be used. 3) In some tissues there is evidence that glycolysis and oxidative metabolism are compartmentalized, with a transfer of lactate and/or pyruvate from glycolytically active cells to ones that depend more on oxidative metabolism. This concept has led to the idea that the retina uses a similar strategy, with lactate being produced in Muller cells and shuttled to neurons. The relatively recent availability of selective blockers of monocarboxylate transport, provides an opportunity to evaluate the importance of such transfer quantitatively in both the inner and outer retina. All the information to be gained is fundamental to understanding how the retina changes in disease, and what the capabilities of the inner and outer retina are for oxidative and glycolytic metabolism under different conditions.