Biophysical properties of a chloride channel in the apical membrane of a secretory epithelial cell.
1. Patch clamp studies on colonic tumor cell line T84 show the presence of chloride channels. 2. The channels are activated by forskolin, PGE2, or 8-Br-cAMP. 3. Single channel conductance was ca 40 pS at the reversal potential, increasing to 70 pS at +80 mV and decreasing to 25 pS at -80 mV. 4. Relative permeabilities were I greater than Br greater than Cl greater than F.
Halm
D R
DR
Department of Physiology and Biophysics, University of Alabama, Birmingham 35294.
Rechkemmer
G
G
Schoumacher
R A
RA
Frizzell
R A
RA
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D018118:Chloride Channels; D002712:Chlorides / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D003110:Colonic Neoplasms / Q000503:physiopathology; D015232:Dinoprostone / Q000494:pharmacology; D004848:Epithelium; D007419:Intestinal Secretions / Q000502:physiology; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials; D008565:Membrane Proteins / Q000502:physiology*; D014407:Tumor Cells, Cultured
D018118:Chloride Channels; D002712:Chlorides; D007473:Ion Channels; D008565:Membrane Proteins; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D015232:Dinoprostone