CHOLINERGIC REGULATION OF INTESTINAL POTASSIUM TRANSPORT

肠道钾转运的胆碱能调节

• 批准号: 3237137
• 负责人: MICHAEL E DUFFEY
• 金额: $ 10.46万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-01-01 至 1992-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3237137
• 关键词: acetylcholine; apical membrane; basolateral membrane; biological fluid transport; calcium metabolism; chloride channels; cholinergic receptors; colon; gastrointestinal absorption /transport; gastrointestinal epithelium; ion transport; laboratory rabbit; ligands; membrane potentials; muscarinic receptor; neural information processing; neurotransmitters; parasympathetic nervous system; potassium channel; secretion; tissue /cell culture

The long term goal of this research is to understand the regulation of fluid and electrolyte transport by the epithelium of mammalian intestine. Here, we will be concerned with the effects of parasympathetic stimulation of the intestinal epithelium. This is a dominant excitatory stimulus for intestinal function during a meal. Parasympathetic stimulation causes Cl- secretion by the intestinal epithelium, by the cellular mechanisms remain largely undefined. This proposal is focused on the mechanisms by which the parasympathetic neurotransmitter, acetylcholine, regulates Cl- secretion. The central hypothesis is that parasympathetic stimulation of Cl- secretion is mediated by basolateral membrane K+ channels provide the driving force for Cl- efflux through apical membrane channels. The techniques of whole-cell voltage-clamp, single-channel recording and intracellular Ca2+ indicator will be used carry-out the proposed research. The research is based on preliminary studies carried out on cultured human colonic epithelial cells (T84 cell line) and has the following Specific Aims: (1) Ionic basis and gating mechanism: We will determine the ionic basis of muscarinic cholinergic agonist-induced whole-cell membrane current oscillations in isolated cells. We will establish whether the underlying channel is gated by membrane voltage, directly by the ligand, or by intracellular Ca2+ release, or both is/are necessary for the Ca2+ oscillations. (3) Membrane location of ion channels: We will determine whether the oscillating ion current is located in the apical or basolateral membrane, since the loci of ion channels determines their role in secretion or absorption. We will determine the sites and properties (eg., voltage dependence, selectivity) of cholinergic agonist-induced K+ and Cl- channels in cultured monolayers of T84 cells, and in the basolateral membrane of acutely dissociated crypts from rabbit distal colon. (4) Integrated response: We will determine whether a hyperpolarization of membrane voltage and intracellular Ca2+ oscillations are part of the Cl- secretory response of intact tissues during cholinergic stimulation.

这项研究的长期目标是了解 哺乳动物肠上皮的流体和电解质传输。 在这里，我们将关注副交感神经刺激的影响 肠上皮。 这是一种主要的兴奋性刺激 一餐期间的肠功能。 副交感神经刺激导致肠道分泌 上皮，通过细胞机制在很大程度上不确定。 这 提案的重点是副交感神经的机制 神经递质（乙酰胆碱）调节Cl-分泌。 中央 假设是副交感神经刺激cl-分泌是介导的 基底外侧膜K+通道为Cl-提供了驱动力 通过顶膜通道的外排。 全细胞电压钳，单渠道记录和 细胞内Ca2+指示器将用于提出的研究。 该研究基于对培养的人进行的初步研究 结肠上皮细胞（T84细胞系），具有以下特定 目的：（1）离子基础和门控机制：我们将确定离子 毒蕈碱胆碱能激动剂引起的全细胞膜电流的基础 孤立细胞中的振荡。 我们将确定是否基础 通道由膜电压，配体直接通过膜电压或 细胞内Ca2+释放，或两者都是Ca2+所必需的 振荡。 （3）离子通道的膜位置：我们将确定 振荡离子电流是否位于顶部还是基底外侧 膜，因为离子通道的位点决定了它们在分泌中的作用 或吸收。 我们将确定位点和属性（例如电压 胆碱能激动剂诱导的K+和Cl-通道的依赖性，选择性） 在T84细胞的培养单层中，以及在基底外侧膜中 急性分离的隐窝与兔远端结肠。 （4）集成 反应：我们将确定膜的超极化是否 电压和细胞内Ca2+振荡是Cl分泌的一部分 胆碱能刺激过程中完整组织的反应。