Title: Voltage-dependent block of endothelial volume-regulated anion channels by calix[4]arenes
Authors: Droogmans, Guillaume ×
Prenen, Jean
Eggermont, Jan
Voets, Thomas
Nilius, Bernd #
Issue Date: Sep-1998
Series Title: American Journal of Physiology. Cell Physiology vol:275 issue:3 Pt 1 pages:C646-52
Abstract: We have studied the effects of calix[4]arenes on the volume-regulated anion channel (VRAC) currents in cultured calf pulmonary artery endothelial cells. TS- and TS-TM-calix[4]arenes induced a fast inhibition at positive potentials but were ineffective at negative potentials. Maximal block occurred at potentials between 30 and 50 mV. Lowering extracellular pH enhanced the block and shifted the maximum inhibition to more negative potentials. Current inhibition was also accompanied by an increased current noise. From the analysis of the calix[4]arene-induced noise, we obtained a single-channel conductance of 9.3 +/- 2.1 pS (n = 9) at +30 mV. The voltage- and time-dependent block were described using a model in which calix[4]arenes bind to a site at an electrical distance of 0.25 inside the channel with an affinity of 220 microM at 0 mV. Binding occludes VRAC at moderately positive potentials, but calix[4]arenes permeate the channel at more positive potentials. In conclusion, our data suggest an open-channel block of VRAC by calix[4]arenes that also depends on the protonation of the binding site within the pore.
ISSN: 0363-6143
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Physiology Section (-)
Laboratory of Ion Channel Research
Department of Cellular and Molecular Medicine - miscellaneous
Laboratory of Cellular Transport Systems
× corresponding author
# (joint) last author

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