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The chloride channel ClC‐2 contributes to the inwardly rectifying Cl − conductance in cultured porcine choroid plexus epithelial cells
Author(s) -
Kajita Hidetoshi,
Omori Koichiro,
Matsuda Hiroko
Publication year - 2000
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2000.t01-1-00313.x
Subject(s) - choroid plexus , dids , forskolin , chloride channel , chemistry , transfection , tetraethylammonium chloride , biophysics , microbiology and biotechnology , niflumic acid , ibmx , extracellular , reversal potential , intracellular , patch clamp , biochemistry , endocrinology , biology , potassium , in vitro , receptor , organic chemistry , membrane , gene , central nervous system
1 The contribution of ClC‐2 protein to the inwardly rectifying Cl − conductance in cultured porcine choroid plexus epithelial cells was investigated using Western analysis and whole‐cell current recordings. 2 Inwardly rectifying currents were elicited by hyperpolarizing voltage at a potential more negative than −50 mV in the presence of intracellular protein kinase A (PKA). The relative halide selectivity estimated from the shift in the reversal potential ( E rev ) was I − > Br − > Cl − > F − . 3 Extracellular vasoactive intestinal peptide (VIP) activated the same currents in a dose‐dependent manner with a half‐maximal concentration of 167·3 nM. H‐89 (a PKA inhibitor) interfered with the current activation by VIP. 4 The Cl − channel was inhibited by external Cd 2+ , Ba 2+ or H + , but only weakly inhibited by known Cl − channel blockers including glibenclamide, NPPB, DIDS and anthracene‐9‐carboxylic acid (9AC). 5 A specific antibody to ClC‐2 detected a 79 kDa protein in porcine choroid plexus cells, which was reduced in cells treated with antisense oligodeoxynucleotide for ClC‐2. Both PKA and VIP failed to activate the inwardly rectifying Cl − currents in cells transfected with the antisense oligodeoxynucleotide, while they activated the currents in cells transfected with GFP alone or the control oligodeoxynucleotide randomized from antisense oligonucleotide. 6 It is concluded that ClC‐2 protein contributes to the inwardly rectifying Cl − conductance in porcine choroid plexus epithelial cells.