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Potent block of volume‐activated chloride currents in endothelial cells by the uncharged form of quinine and quinidine
Author(s) -
Voets Thomas,
Droogmans Guy,
Nilius Bernd
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15616.x
Subject(s) - quinidine , quinine , chemistry , chloride , biophysics , pharmacology , patch clamp , chloride channel , extracellular , biochemistry , receptor , medicine , biology , organic chemistry , malaria , immunology
1 . The effects of quinine and quinidine on the volume‐activated chloride current ( I Cl(vol) ) in cultured endothelial cells from bovine pulmonary artery were studied by use of the whole‐cell patch‐clamp technique. 2 . At pH 7.4 both quinine and quinidine induced a fast and reversible block of I Cl(vol) with K i values of 20 ± 4 μ m and 30 ± 10 μ m , respectively. 3 . The blocking efficiency of both drugs increased dramatically with increasing extracellular pH, indicating that the blockade is mediated by the uncharged form of quinine and quinidine. 4 . These results suggest a hydrophobic interaction with high affinity between volume‐activated chloride channels and uncharged quinine and quinidine within the membrane bilayer of endothelial cells.