WATER AND ELECTROLYTE MOVEMENT IN RENAL TUBULES

这项提议的长期目标是提供新的和有意义的 与溶质运移相关的结构-功能关联数据 沿着哺乳动物的肾小管。这些实验描述了我们的焦点 主要关注收集管道，并将主要重点放在 血管紧张素II(ALL)在间质细胞调节中的作用 结构和功能，特别是在跨上皮细胞的控制中 H+和HCO3-转运。该提案包括四个部分，其中明确 勾勒出需要检验的具体目标和假设。 在特定的目标I，我们将检查ALL对超微结构的影响 用于识别特定间质细胞的间质细胞 对所有人作出反应并决定所有人对 免疫金细胞化学法检测H+-ATPase的亚细胞分布。 有待检验的假设：特定的间质细胞亚型为 ALL对H+-ATPase活性和酸碱的影响 在收集管道中的传输。 特效靶II ALL对H+-ATPase活性的影响 参与调节这些效应的信号转导通路将 在显微解剖的收集管段中进行研究。假设为 经测试：ALL对大鼠心肌细胞H+-ATPase活性的抑制作用 集合管是通过特异的AT1受体和激活 将被识别的不同的信号系统。 在特定的目标III中，我们将确定表达和细胞 全受体异构体mRNA在集合管的定位 定量逆转录聚合酶链式反应和原位杂交检测效果 酸碱扰动对ALL受体基因表达的影响。假设 待测：所有受体的mRNA表达在不同的 插层细胞的数量，并受酸碱的影响 微扰。 在特定的目标四中，我们将确定所有元素对质子和 小苏打在兔离体脑皮质收集中的转运 导入并鉴定应答的间质细胞亚型(S) 全。有待检验的假设：ALL刺激B型HCO3分泌 嵌合细胞及其抑制A型嵌合细胞分泌H+的作用 在大脑皮层收集管中。 本提案中描述的实验旨在继续我们的 长期致力于划定结构和功能 肾小管的特征，特别是为了建立 插层细胞在酸碱调节“微调”中的作用 被肾脏击倒。更好地理解控制H+的机制 和HCO3，肾小管这一区域的运输将使 医生将处理复杂的酸碱平衡临床问题 往往是危及生命的，拥有更多的专业知识和成功。

The long-term objective of this proposal is to provide new and meaningful structural-functional correlative data as it relates to solute transport along the mammalian renal tubule. The experiments described focus our attention primarily on the collecting duct and place a major emphasis on the role of angiotensin II (All) in the regulation of intercalated cell structure and function and specifically in the control of transepithelial H+ and HCO3- transport. The proposal includes four sections with clearly delineated specific aims and hypotheses to be tested. In Specific Aim I we will examine the effect of All on the ultrastructure of intercalated cells to identify specific intercalated cell subpopulations that respond to All, and determine the effect of All on the subcellular distribution of H+ATPase by immunogold cytochemistry. Hypothesis to be tested: Specific intercalated cell subtypes are responsible for the effect of All on H+-ATPase activity and acid-base transport in the collecting duct. In Specific Aim II the effects of All on H+-ATPase activity and the signalling transduction pathways involved in mediating these effects will be studied in microdissected collecting duct segments. Hypothesis to be tested: The inhibitory effect of All on H+-ATPase activity in the collecting duct is mediated via specific AT1 receptors and activation of distinct signalling systems which will be identified. In Specific Aim III we will determine the expression and cellular location of All receptor isoform mRNA in the collecting duct by quantitative RT-PCR and in situ hybridization and determine the effect of acid-base perturbations on All receptor mRNA expression. Hypothesis to be tested: All receptor mRNA expression varies between different populations of intercalated cells and is influenced by acid-base perturbations. In Specific Aim IV we will determine the effect of All on proton and bicarbonate transport in the isolated perfused rabbit cortical collecting duct and identify the subtype(s) of intercalated cells that responds to All. Hypothesis to be tested: All stimulates HCO3 secretion by type B intercalated cells and inhibits H+ secretion by type A intercalated cells in the cortical collecting duct. The experiments described in this proposal are intended to continue our long-term commitment to delineate the structural and functional characteristics of the renal tubule and specifically to establish the role of intercalated cells in the "fine-tuning" of acid-base regulation by the kidney. A better understanding of the mechanisms that control H+ and HCO3, transport in this region of the renal tubule will enable physicians to manage complicated clinical problems of acid-base balance that are often life-threatening with greater expertise and success.