Emile L. Boulpaep

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We have used pH-, Na-, and Cl-sensitive microelectrodes to study basolateral HCO3- transport in isolated, perfused proximal tubules of the tiger salamander Ambystoma tigrinum. In one series of experiments, we lowered basolateral pH (pHb) from 7.5 to 6.8 by reducing [HCO3-]b from 10 to 2 mM at a constant pCO2. This reduction of pHb and [HCO3-]b causes a(More)
Using pH-sensitive microelectrodes to measure intracellular pH (pHi) in isolated, perfused proximal tubules of the tiger salamander Ambystoma tigrinum, we have found that when cells are acid-loaded by pretreatment with NH+4 in a nominally HCO3--free Ringer, pHi spontaneously recovers with an exponential time course. This pHi recovery, which is indicative of(More)
Two electroneutral, Na+-driven HCO3- transporters, the Na+-driven Cl-/HCO3- exchanger and the electroneutral Na+/HCO3- cotransporter, have crucial roles in regulating intracellular pH in a variety of cells, including cardiac myocytes, vascular smooth-muscle, neurons and fibroblasts; however, it is difficult to distinguish their Cl- dependence in mammalian(More)
Bicarbonate transporters are the principal regulators of pH in animal cells, and play a vital role in acid-base movement in the stomach, pancreas, intestine, kidney, reproductive system and central nervous system. The functional family of HCO3- transporters includes Cl- -HCO3- exchangers, three Na+/HCO3- cotransporters, a K+/HCO3- cotransporter, and a(More)
M-1 cells, derived from a microdissected cortical collecting duct of a transgenic mouse, grown to confluence on a permeable support, develop a lumen-negative amiloride-sensitive transepithelial potential, reabsorb sodium, and secrete potassium. Electron micrographs show morphological features typical of principal cells in vivo. Using the patch clamp(More)
The transport of chloride across theNecturus proximal tubule cell was studied in the doubly-perfused kidney using conventional, chloride-sensitive and pH-sensitive microelectrodes. Lowering chloride activity in the basolateral solution results in a reduction in intracellular Cl− activity (a Cl i ). This reduction ina Cl i is inhibited by removing either HCO(More)
The regulation of K+-channel activity from the apical membrane of the rabbit cortical collecting tubule was studied using the patch-clamp technique. Using inside-out patches, channel open probability was determined as a function of calcium and barium concentration and transmembrane potential. Channel open probability was increased by raising bath(More)
The chloride conductance of the basolateral cell membrane of theNecturus proximal tubule was studied using conventional and chloride-sensitive liquid ion exchange microelectrodes. Individual apical and basolateral cell membrane and shunt resistances, transepithelial and basolateral, cell membrane potential differences, and electromotive forces were(More)