TRANSITIONS AND TRANSPORT IN GASTRIC MUCOSA

这项工作的总体目标是了解膜机制。 参与胃氧合细胞和胃表面细胞的C1分泌 以及不同的细胞过程，这些过程服务于调节 这架运输机。第一个目标是研究膜Na-H和 C1-HCO3交换器可能对这种传输起到了作用。一个 细胞质捕获的荧光染料(所谓的BCECF)将用于 定量监测离体胃腺体细胞pH值(PHC) 从兔胃中分离纯化的氧合细胞和表面细胞。 在各种实验治疗期间的PHC测量(更改 钠、氯和HCO3/CO2的溶液浓度；特定缓蚀剂的使用 如用于Na-H交换的阿米洛利和用于C1-HCO3交换的SITE)将允许 以确定这样的交换器是否在胃粘膜中起作用。 这些数据还将提供有关以下能力的独特信息 胃细胞调节它们的PHC。有关C1-HCO3的更多信息 将通过监测荧光染料的通量来获得交换器 NBD-牛磺酸，它只通过红细胞膜 交易所。第二个目标是测量快速的、单向的 22 Na，36 Cl和42K(或86 Rb)在分离的兔表面细胞和 以确定这些细胞是否含有其他机制 (例如，NaCl2或NaKC12)和用于积累C1的交换器。这个 最终目标是确定氧合作用的一些机制 细胞和表面细胞调节这些膜交换器的活性。 和联合运输者。因为[Ca]c被认为是细胞内的第二个 多种细胞类型(包括胃)的信使，我们将利用 胞质捕捉荧光，钙敏感染料(所谓的Quin 2)，用于 定量测定[Ca]c在氯迁移和 细胞的活动已经改变了。[Ca]c、PHc之间的相互作用 和其他细胞第二信使(如环核苷酸、C-激酶) 也将接受调查。这些实验将产生关于 胃细胞如何产生和控制C1分泌。因为有很多 胃细胞转运H、C_1和OH/HCO_3的直接关系 这项工作将对以下能力产生影响：(1)氧合成酶 细胞分泌HCl；(Ii)表面细胞分泌OH/HCO3，从而 维持所谓的粘液/HCO3屏障；(Iii)两种细胞类型均可 在高酸性的胃面前调节它们的细胞质pH 内容。

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.