TRANSITIONS AND TRANSPORT IN GASTRIC MUCOSA

胃粘膜的转变和运输

• 批准号: 3226420
• 负责人: TERRY E MACHEN
• 金额: $ 8.4万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1977
• 资助国家: 美国
• 起止时间: 1977-04-01 至 1989-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3226420
• 关键词: acetazolamide; acid base balance; anions; barium; calcium; cations; electrophysiology; gastric mucosa; gastrointestinal absorption /transport; histamine; hypoxia; ion transport; membrane permeability; membrane potentials; newborn animals; ouabain; oxygen consumption; secretion; theophylline

The general goals of this work are to understand the membrane mechanisms involved in C1 secretion by oxyntic cells and surface cells of the gastric mucosa as well as the different cellular processes which serve to regulate this transport. The first aim is to investigate whether membrane Na-H and C1-HCO3 exchangers may be contributing to this transport. A cytoplasmic-trapped, fluorescent dye (so-called BCECF) will be used to monitor quantitatively the cellular pH (pHc) in isolated gastric glands and in isolated purified oxynthic cells and surface cells from rabbit stomach. Measurements of Phc during a variety of experimental treatments (altered solution concentrations of Na, C1 and HCO3/CO2; use of specific inhibitors like amiloride for Na-H exchange and SITS for C1-HCO3 exchange) will allow us to determine whether such exchangers are operational in gastric mucosa. These data will also provide unique information regarding the ability of gastric cells to regulate their pHc. Further information about the C1-HCO3 exchnager will be obtained by monitoring the flux of the fluorescent dye NBD-taurine, which moves across red cell membranes only through the exchanger. The second goal is to measure rapid, unidirectional uptakes of 22 Na, 36 C1 and 42K (or 86 Rb) in isolated rabbit surface cells and oxynthic cells to determine whether these cells contain other mechanisms (e.g. NaC1 or NaKC12) besides the exchangers for accumulating C1. The final goal is to determine some of the mechanisms by which the oxynthic cells and surface cells regulate the activity of these membrane exchangers and co-transporters. Since [Ca]c has been implicated as a cellular second messenger for many cell types (including the stomach), we will utilize the cytoplasmic-trapped fluroescent, Ca-sensitive dye (so-called Quin 2) for quantitatively measuring [Ca]c during conditions in which C1 transport and the activity of the cells has been altered. Interactions among [Ca]c, pHc and other cellular second messengers (e.g. eyclic nucleotides, C-kinase) will also be investigated. These experiments will yield information about how gastric cells generate and control C1 secretion. Since there are many direct relationships among H, C1 and OH/HCO3 transport by gastric cells, this work will have implications about the ability of: (1) the oxyntic cells to secrete HC1; (ii) the surface cells to secrete OH/HCO3 and thereby maintain the so-called mucus/HCO3 barrier; (iii) both cell types to regulate their cytoplasmic pH in the face of the highly acidic stomach contents.

这项工作的总体目标是了解膜机制 参与胃泌酸细胞和表面细胞的C1分泌 粘膜以及不同的细胞过程，其用于调节 这个运输。 第一个目的是研究膜Na-H和 C1-HCO 3交换器可能有助于这种运输。 一 胞质捕获的荧光染料（所谓的BCECF）将用于 定量监测离体胃腺中的细胞pH值（pHc）， 分离纯化的兔胃泌酸细胞和表面细胞。 在各种实验治疗期间的Phc测量（改变 Na、Cl和HCO 3/CO2的溶液浓度;特定抑制剂的使用 如用于Na-H交换的阿米洛利和用于C1-HCO 3交换的SITS）将允许 我们来确定这种交换器是否在胃粘膜中起作用。 这些数据还将提供有关 胃细胞调节其pH。 关于C1-HCO 3的更多信息 通过监测荧光染料的通量， NBD-牛磺酸，它只能穿过红细胞膜， 交换器 第二个目标是测量快速，单向摄取 22 Na、36 Cl和42 K（或86 Rb）， 以确定这些细胞是否包含其他机制 (e.g. NaCl或NaKCl 2）。 的 最终的目标是确定一些机制， 细胞和表面细胞调节这些膜交换剂的活性 和协同转运体。 由于[Ca]c被认为是细胞中的第二个 对于许多细胞类型（包括胃）的信使，我们将利用 细胞质捕获的荧光，钙敏感染料（所谓的Quin 2）， 在C1运输和 细胞的活性被改变了 [Ca]c、pHc之间的相互作用 和其他细胞第二信使（例如环状核苷酸、C-激酶） 也将被调查。 这些实验将产生关于 胃细胞如何产生和控制C1分泌。 因为有许多 胃细胞的H、C1和OH/HCO 3转运之间的直接关系， 这项工作将对以下能力产生影响：（1） 细胞分泌HCl;（ii）表面细胞分泌OH/HCO 3，从而 维持所谓的粘液/HCO 3屏障;（iii）两种细胞类型， 调节细胞质的pH值，以应对高度酸性的胃 内容.