Rat Retina-RPE-Choroid Preparation: Electrophysiological

RPE是与视网膜光感受器相互作用并帮助维持视觉功能的单层色素细胞。我们已经开发了一种新的制剂来研究包括神经视网膜在内的大鼠RPE生理学。将视网膜-视网膜色素上皮-脉络膜（R-RPE-Ch）制备物安装在允许视网膜和脉络膜浴独立灌注的Ussing室中。完整单层的平均（+/- SD）跨上皮电位为4.3 +/- 1.0 mV，总跨上皮电阻为152 +/- 37 ohm*cm^2（n =10）。在其他哺乳动物的视网膜色素上皮制剂，我们发现钡敏感的K通道的顶端和基底外侧膜。基底外侧膜细胞内微电极显示基础钾（[K]o）的阶跃增加使基底外侧膜去极化~8 mV（n=2），并被钡阻断。降低顶端[K]o模拟光起始并使顶端膜超极化;增加顶端[K]o使顶端膜去极化约6 mV（n=3）。[K]o反应被钡阻断。R-RPE-Ch制剂被开发用于研究光诱导的RPE生理学变化，并提供体内功能的体外模型。它可以用来分析光诱发的RPE生理发生在最好的改变？这种疾病被认为是由基底外侧膜钙激活氯离子通道突变引起的。

The RPE is a monolayer of pigmented cells that interact with retinal photoreceptors and helps maintain visual function. We have developed a new preparation to study RPE physiology in rat that includes the neural retina. The retina-retinal pigment epithelium-choroid (R-RPE-Ch) preparation was mounted in an Ussing chamber which allowed independent perfusion of retinal and choroidal baths. The intact monolayer had a mean (+/- SD) transepithelial potential of 4.3 +/- 1.0 mV and a total transepithelial resistance of 152 +/- 37 ohm*cm^2 (n =10). As in other mammalian RPE preparations, we found barium-sensitive K channels at the apical and basolateral membranes. Intracellular microelectrodes at the basolateral membrane showed that step increases of basal potassium ([K]o) depolarized the basolateral membrane ~8 mV (n=2) and were blocked by barium. Decreasing apical [K]o mimics light-onset and hyperpolarizes the apical membrane; increasing apical [K]o depolarized the apical membrane by ~6 mV (n=3). [K]o responses were blocked by barium. The R-RPE-Ch preparation was developed to study light-induced changes in RPE physiology, and provides an in-vitro model of in-vivo function. It can be used to analyze light-evoked alterations in RPE physiology that occur in Best?s disease, which is thought to result from a mutation in basolateral membrane calcium-activated chloride channels.