ELECTROPHYSIOLOGY OF GASTRIC ION TRANSPORT

这个项目的总体目标是使用电生理学 方法：(I)确定膜机制 含氧酸(OC，酸分泌)和表面上皮(SEC，粘液- 胃底的分泌细胞用来主动运输H， Cl，Na和HC03：和(Ii)表征了 细胞旁分流。因为眼底的秒和眼底细胞 Antrum具有非常相似的传输特性，测量结果将 也可延伸至上颌窦。孤立性胃坏死 将使用粘膜和胃窦，因为它们表现出相同的 离子输运特性与哺乳动物的相同 它们的组织结构更简单，细胞更大，而且 在体外更健壮。一种测量小尺寸的振动探头 细胞外电流将被用来确定电导 SECS和OCS各自的属性。标准 微电极被用来刺穿SEC和OCS并获得 膜电位测量。该振动探头和 微电极将结合使用，以获得定量 粘液和粘液电导特性的测量 两个细胞的浆膜和分流管(细胞间) 类型。初步数据显示，SEC和OCS有很大的 不同的膜传输和电导特性以及 也有不同的分流装置。双管离子选择电极 将用来测定细胞内(K)、(Cl)、(Na)和pH 并对非导电运动进行评估 离子通过共转运体(例如KClsymport)和交换体(例如 CL/HC03或Na/H对位)。使用这些技术， 粘膜的通透性、导电性和运输性 OCS和SECS和SECS的浆膜对Na+，K+，Cl- 将测定HC03和H+。另外，电导 OCS之间和Secs之间的分流特性可以是 下定决心。这一信息显然对 我们对胃如何工作的全面了解。此外，由于 胃的“屏障”功能必须以某种方式与 细胞和分流的能力，排除H+，这项工作还应 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.