ELECTROPHYSIOLOGY OF GASTRIC ION TRANSPORT

该项目的总体目标是使用电生理学 方法：（一）确定膜机制， 泌酸（OC，酸分泌）和表面上皮（SEC，粘液- 胃底的分泌）细胞用于主动转运H， Cl、Na和HC 03：和（ii）表征所述化合物的性质。 细胞旁分流术 因为眼底的SECs和 胃窦具有非常相似的传输特性，测量将 也可以延伸到胃窦。 分离的胃蜜环菌 将使用粘膜和胃窦，因为它们表现出相同的 离子传输特性与哺乳动物相似， 它们在组织学上更简单，细胞更大， 在体外更稳定。 一个振动探针， 细胞外电流将用于确定电导 SEC和业主立案法团各自的属性。 标准 微电极用于刺穿SEC和OC， 膜电位测量。 振动探头和 将结合使用微电极以获得定量的 测量粘膜的电导特性， 两个细胞的浆膜和分流（细胞间） 类型 初步数据显示，SEC和业主立案法团有非常 不同的膜转运和电导性质， 还有不同的分流器 双管离子选择电极 将用于测定细胞内（K）、（Cl）、（Na）和pH值 稳定状态，并评估非导电运动 离子通过共转运体（如KCl同向转运）和交换体（如 Cl/HC 03或Na/H反向转运）。 使用这些技术， 粘膜的渗透性、传导性和运输特性 OC和SECs和SECs对Na+，K+，Cl-的渗透和渗透 将测定HC 〇 3和H+。 此外，电导 业主立案法团之间和SECS之间的分流的性质可以是 测定 这一信息将是非常重要的， 我们对胃如何工作的全面了解。 此外，由于 胃的“屏障”功能一定与胃的 细胞和分流排除H+的能力，这项工作也应该 提供关于这个问题的有用信息。

The overall goals of this project are to use electrophysiological methods to: (i) determine the membrane mechanisms which oxyntic (OC, acid-secreting) and surface epithelial (SEC, mucus- secreting) cells of the gastric fundus use to actively transport H, Cl, Na and HC03: and (ii) characterize the properties of the paracellular shunt. Because SECs of fundus and the cells of antrum have very similar transport properties, measurements will also be extended to the antrum. The isolated Necturus gastric mucosa and antrum will be used because they exhibit the same ionic transport properties as their mammalian counterparts yet they are histologically simpler, have larger cells and are much more robust in vitro. A vibrating probe which measures small extracellular currents will be used to determine the conductance properties of the SECs and OCs individually. Standard microelectrodes are used to impale both SECs and OCs and obtain membrane potential measurements. The vibrating probe and microelectrodes will be used in combination to obtain quantitative measurements of the conductance properties of the mucosal and serosal membranes and shunts (between cells) of the two cell types. Preliminary data indicate that SECs and OCs have very different membrane transport and conductance properties and also different shunts. Double-barreled ion selective electrodes will be used to determine intracellular (K), (Cl), (Na) and pH in the steady state and also to assess the non-conductive movements of ions via cotransporters (e.g. KCl symport) and exchangers (e.g. Cl/HC03 or Na/H antiport). Using these techniques the permeability, conductive and transport properties of the mucosal and serosal membranes of OCs and SECs and SECs to Na+, K+, Cl- HC03 and H+ will be determined. Also, the conductance properties of the shunts between OCs and between SECS can be determined. This information will be of obvious importance for our overall knowledge of how the stomach works. Also, since the "barrier" function of the stomach must somehow be related to the ability of the cells and shunt to exclude H+, this work should also yield useful information about this question.