INTESTINAL SECRETORY MECHANISMS AND ANTIDIARRHEAL DRUGS

一种保留特定电解质的培养上皮细胞系 运输功能可以作为研究这些功能的模型系统。 培养细胞允许在均相条件下研究转运过程 不受其他细胞类型混杂影响的一组细胞。这是 应该允许更好和更具体地识别 运输现象中涉及的一系列细胞事件， 从受体结合到激活细胞内扩增 不同转运途径对血浆刺激的机制 薄膜。受体介导的离子转运的初步表征 人结肠上皮细胞系T84的特性 细胞系，提示该细胞系可能是有用的分泌物。 模型系统。 在这一建议中，氯离子和钾离子通道以及钠、钾、氯离子的作用 CAMP和钙离子介导的分泌共转运将进一步 在T84细胞中进行了研究。初步研究表明，这些运输 多种途径与分泌机制密切相关。三种方法 将被用来研究离子传输。1)Ussing会议室，学习 离子的跨上皮运动。CAMP与钙离子介导的协同作用 将测试分泌物，并参与运输途径和 将研究分泌过程中的细胞内介体。2) 放射性核素在整个细胞的摄取和外流，以直接验证 研究涉及的具体运输途径，并研究它们的相互作用。3) 纯化的刷状缘膜和基侧膜中的转运研究 定位运输路径并确定其运输特征。 建议的研究应可让我们找出不同的运输途径。 在参与分泌活动的质膜上提供 关于细胞内扩增机制的信息。有关的信息 转运通路的抑制与细胞内信号转导的阻断 健全机制应该为发展提供合理的途径 止泻药。

A cultured epithelial cell line which retains specific electrolyte transport functions may serve as a model system to study those functions. Culture cells allow the transport processes to be studied in a homogeneous group of cells free of the confounding effect of other cell types. This is an advantaje which should allow better and more specific identification of the sequence of cellular events involved in a transport phenomenon, beginning with receptor binding to activation of intracellular amplifying mechanisms to stimulation of various transport pathways on the plasma membrane. Initial characterization of receptor-mediated ion transport properties in the T84 colonic cell line, an established human epithelial cell line, suggests that this cell line may serve as a useful secretory model system. In this proposal, the role of Cl- and K+ channels and Na+,K+,Cl- cotransport in cAMP and Ca++ mediated secretion will be further investigated in T84 cells. Initial studies suggest that these transport pathways are intimately involved in secretory mechanisms. Three methods will be used to study ion transport. 1) The Ussing chamber, to study transepithelial movement of ions. Synergism between cAMP and Ca++ mediated secretion will be tested, and the involvement of transport pathways and intracellular mediators in secretory processes will be studied. 2) Radionuclide uptake and efflux in whole cells to directly verify the specific transport pathways involved and to study their interactions. 3) Transport studies in purified brush border and basolateral membranes to localize transport pathways and determine its transport characteristics. The proposed studies should allow us to identify various transport pathways on the plasma membrane involved in the secretory events and provide information about the intracellular amplifying mechanisms. Information on the inhibition of transport pathways and the interruption of intracellular amplifying mechanisms should provide a rational approach to the development of antidiarrheal medications.