Single-channel analysis of a ClC-2-like chloride conductance in cultured rat cortical astrocytes.
The single-channel behavior of the hyperpolarization-activated, ClC-2-like inwardly rectifying Cl- current (IClh), induced by long-term dibutyryl-cyclic-AMP-treated cultured cortical rat astrocytes, was analyzed with the patch-clamp technique. In outside-out patches in symmetrical 144 mM Cl-solutions, openings of hyperpolarization-activated small-conductance Cl channels revealed burst activity of two equidistant conductance levels of 3 and 6 pS. The unitary openings displayed slow activation kinetics. The probabilities of the closed and conducting states were consistent with a double-barrelled structure of the channel protein. These results suggest that the astrocytic ClC-2-like Cl- current Iclh is mediated by a small-conductance Cl channel, which has the same structural motif as the Cl- channel prototype CIC-0.
Institute of Cybernetics and Biophysics, CNR, Genoa, Italy. nobile@icb.ge.cnr.it
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D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D000090007:CLC-2 Chloride Channels; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D004553:Electric Conductivity; D015640:Ion Channel Gating / Q000187:drug effects; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D018408:Patch-Clamp Techniques; D051381:Rats
D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D003994:Bucladesine