Rat Retina-RPE-Choroid Preparation: Electrophysiological

RPE是色素细胞的单层，与视网膜光感受器相互作用，帮助维持视觉功能。我们开发了一种新的制剂来研究大鼠的RPE生理学，包括神经视网膜。视网膜-视网膜色素上皮-脉络膜(R-RPE-CH)制剂安装在允许视网膜和脉络膜浴液独立灌流的Ussing小室中。完整单层的平均跨上皮电位(+/-SD)为4.3+/-1.0 mV，总跨上皮阻力为152+/-37欧姆*厘米2(n=10)。与其他哺乳动物RPE制剂一样，我们在顶膜和基侧膜上发现了对钡敏感的K通道。基底侧膜的细胞内微电极显示，递增的基础钾([K]o)使基底侧膜去极化约8 mV(n=2)，并被Ba2+阻断。降低顶端[K]o可模拟入光并使顶膜超极化；增加顶端[K]o可使顶膜去极化约6 mV(n=3)。[K]O反应被Ba2+阻断。R-RPE-CH制剂是为了研究光诱导的RPE生理变化而开发的，并提供了一种体内功能的体外模型。它可用于分析Best？S病中发生的光诱发的RPE生理学改变，该疾病被认为是由于基底膜钙激活的氯离子通道突变所致。

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.