Shear stress induced membrane currents and calcium transients in human vascular endothelial cells |
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Authors: | Gero Schwarz Guy Droogmans Bernd Nilius |
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Affiliation: | (1) Max Planck Group Molecular and Cellular Physiology, O-6900 Jena, Federal Republic of Germany;(2) Department of Physiology, Catholic University Leuven, B-3000 Leuven, Belgium;(3) Laboratorium voor Fysiologie, Campus Gasthuisberg, B-3000 Leuven, Belgium |
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Abstract: | We have measured membrane currents induced by shear stress together with intracellular calcium signals in endothelial cells from human umbilical cord veins. In the presence of extracellular calcium (Ca2+]o), shear stress induced an inward current at a holding potential of 0 mV which is accompanied by a rise in intracellular Ca2+ ([Ca2+]i). In the absence of extracellular calcium shear stress was unable to evoke a calcium signal but still induced a membrane current. The voltage dependence of the shear stress induced current was obtained from difference currents evoked by linear voltage ramps before and during application of shear stress. Its reversal potential Erev shifted from –2.3±0.8 mV (n=4) in a nominally Ca2+ free solution to +1.5±1.6 mV at 1.5 mM [Ca2+]o (n=4) and to +21.9±4.4 mV (n=7) at 10 mM [Ca2+]o. From our data we conclude that shear stress opens an ion channel that is 12.5±2.9 (n=7) times more permeable for calcium than for sodium or cesium. |
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Keywords: | endothelium shear stress Ca2+-permeable ion channels intracellular calcium |
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