ACTIVE POTASSIUM TRANSPORT ACROSS COLONIC EPITHELIUM

该项目的中心目标是描述 上皮细胞的定位和运输机制负责 哺乳动物结肠中活性K的分泌和吸收 以及调节这些过程的机制。 哺乳动物的结肠通过过程吸收和分泌液体 分别依赖于钠的吸收和氯的分泌。 活性K的分泌和吸收发生并可能与 既有钠吸收细胞，也有氯分泌细胞。地点 将使用以下方法确定K个运输过程的 电子常规和离子选择性微电极 组织成分和荧光的显微探针分析 活组织的显微镜检查。电生理学技术将是 用来检测细胞膜电势的变化 和细胞内离子活性与钾分泌和 吸收。细胞内Na、K的电子探针分析 而氯的浓度将确定其形态位置。 活化钾的分泌和吸收。K的可能性 吸收与胃酸分泌相结合将使用 PH荧光探针与直接可视化技术的结合 使用差示干涉衬度显微镜。监管 将使用膜片钳技术来检测钾转运 和形态技术。钾离子和氯离子通道的激活 运输刺激器将通过单通道进行检查 分离的结肠上皮细胞和原代培养的记录 这些细胞。刺激氯的分泌改变细胞的形态 结肠上皮中的空泡状柱状细胞型。 所涉及的形态变化的直接可视化 对分泌物的刺激将通过区分来完成 干涉衬度显微镜。这些研究将提供一个 活化钾转运位置的完整表征 结肠上皮，并允许了解离子 与肠道液体吸收和运输相关的转运事件 分泌物。

The central goal of this projet is the characterization of the epithelial location and transport mechanisms responsible for active K secretion and absorption across the mammalian colon as well as the mechanisms that regulate these processes. Mammalian colon absorbs and secretes fluid by processes dependent on Na absorption and Cl secretion, respectively. Active K secretion and absorption occur and could be associated with either Na absorbing cells or Cl secreting cells. The location of the K transport processes will be determined using conventional and ion-selective microelectrodes, electron microprobe analysis of tissue composition, and fluorescence mocroscopy of living tissue. Electrophysiologic techniques will be employed to detect changes in cell membrane electrical potential and intracellular ion activity consistent with K secretion and absorption. Electron microprobe analysis of intracellular Na, K and Cl concentration will confirm the morphologic location of active K secretion an dabsorption. The possibility that K absorption is coupled to acid secretion will be examined using fluorescent probes of pH in conjunction with direct visualization using differential interference contrast microscopy. Regulation of K transport will be examined using the patch clamp technique and morphologic techniques. Activation of K and Cl channels by stimulators of transport will be examined with single channel recording from isolated colonic epithelia and primary cultures of these cells. Stimulation of Cl secretion alters the morphology of the vacuolated, columnar cell type in the colonic epithelium. Direct visualization of the morphologic changes involved in stimulation of secretion will be accomplished with differential interference contrast microscopy. These studies will provide a complete characterization of the location of active K transport in the colonic epithelium and permit an understanding of the ion transport events associated with intestinal fluid absorption and secretion.