MECHANISM OF RENAL ACID-BASE HOMEOSTASIS

拟议议定书的主要目标是更明确地界定 通过直接测定pH值的尿酸化机制， pCO 2和总CO2浓度在体内的可及肾单位的 使用标准皮质和乳头状微穿刺的大鼠肾脏 技术. 在这一系列的研究中，三个具体领域将是 （1）确定地震的大小和方向; 近曲小管和远曲小管pH不平衡，（2） 管腔碳酸酐酶对重吸收的贡献 体内灌注的离体近端小管，和（3）测定pH， pCO 2和肾脏可及节段中的总CO2浓度 乳头 这些研究将利用开发的pH和pCO 2微电极 在我们的实验室应用于大鼠显微穿刺，以及 Vurek微量热法测定CO2总量 浓度. 这些研究应允许区分两者 提出的碳酸氢盐重吸收机制：1）H+分泌，或2） 初级HCO-3重吸收 总之，拟议的研究将利用 微电极和微量热技术， 直接应用皮质和乳头状的酸碱平衡 微穿刺和体内微灌注技术。

The primary objective of the proposed protocol is to more clearly define the mechanism(s) of urinary acidification by the direct determination of pH, pCO2, and total CO2 concentration in vivo in the accessible nephrons of the rat kidney utilizing standard cortical and papillary micropuncture techniques. In this series of studies, three specific areas will be investigated: (1) determination of the magnitude and direction of the disequilibrium pH in proximal and distal convoluted tubules, (2) contribution of luminal carbonic anhydrase to bicarbonate reabsorption in the in vivo perfused isolated proximal tubule, and (3) determination of pH, pCO2, and total CO2 concentration in the accessible segments of the renal papilla. These studies will utilize pH and pCO2 microelectrodes developed in our laboratory for application in rat micropuncture, as well as the microcalorimetric method of Vurek for determination of total CO2 concentration. These studies should allow differentiation between the two proposed mechanisms of bicarbonate reabsorption: 1) H+ secretion, or 2) primary HCO-3 reabsorption. In summary, the proposed studies will utilize microelectrode and microcalorimetric techniques in concern to evaluate acid-base homeostasis directly by application of cortical and papillary micropuncture and in vivo microperfusion techniques.