Abstract
Chloride channels are important for astrocytic volume regulation and K+ buffering. We demonstrate functional expression of a hyperpolarization-activated Cl- current in a subpopulation of astrocytes in acute slices or after fresh isolation from adult brain of GFAP/EGFP transgenic animals in which astrocytes are selectively labeled. When Na+ and K+ were substituted with NMDG+ and Cs+ in extra- and intracellular solutions, an inward current was observed at negative membrane potentials. The current displayed features as described for a Cl- current characterized in cultured astrocytes: it activated time dependently at potentials negative to -40 mV, displayed no inactivation within 1 s, and was inhibited reversibly by submicromolar concentrations of Cd2+. The current was not detectable in astrocytes from ClC-2 knockout mice, indicating that the ClC-2 chloride channel generated the conductance. Current density was significantly lower in a corresponding population of astrocytes isolated from immature brain and in reactive astrocytes within a lesion site.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Astrocytes / cytology
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Astrocytes / drug effects
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Astrocytes / metabolism*
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Brain / cytology
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Brain / growth & development*
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Brain / metabolism*
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Brain Injuries / genetics
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Brain Injuries / metabolism*
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CLC-2 Chloride Channels
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Cadmium / pharmacology
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Cell Membrane / drug effects
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Cell Membrane / metabolism*
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Cerebral Cortex / cytology
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Cerebral Cortex / growth & development
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Cerebral Cortex / metabolism
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Cesium / pharmacology
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Chloride Channels / deficiency*
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Chloride Channels / genetics
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Chlorides / metabolism
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Gene Expression Regulation, Developmental / genetics
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Glial Fibrillary Acidic Protein / metabolism
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Gliosis / genetics
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Gliosis / metabolism
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Green Fluorescent Proteins
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Hippocampus / cytology
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Hippocampus / growth & development
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Hippocampus / metabolism
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Luminescent Proteins
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Membrane Potentials / drug effects
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Membrane Potentials / physiology
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Mice
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Mice, Knockout
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Mice, Transgenic
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Organ Culture Techniques
Substances
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CLC-2 Chloride Channels
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Chloride Channels
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Chlorides
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Glial Fibrillary Acidic Protein
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Luminescent Proteins
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Cadmium
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Green Fluorescent Proteins
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Cesium