An outwardly rectifying and deactivating chloride channel expressed by interstitial cells of cajal from the murine small intestine.
Recent studies have suggested a role for a chloride current in the modulation of pacemaker potentials generated by interstitial cells of Cajal. Patch-clamp recordings were made from inside-out patches of cultured interstitial cells of Cajal from the murine small intestine. The majority of patches were quiescent immediately after excision, but in some patches currents activated spontaneously after a period of 10 min to 1 h. Currents could also be activated by strongly polarizing the patch. It was found that the currents activated in both cases included a chloride channel. This channel could also be activated by ATP and the catalytic subunit of protein kinase A. The channel had conductance states (+/-SD) of 53 +/- 25.35, 126 +/- 21.44, 180 +/- 12.57 and 211 +/- 8.86 pS. It was outwardly rectifying (as a function of open probability) and deactivated (i.e., gave a tail current) but showed no inactivation. The permeability sequence of the channel was I(-)>>Br(-)>or=Cl(-)>Asp(-). It was unaffected in magnitude or rectification by changing the free Ca2+ concentration of the bath between <10 nM, 100 nM (control) and 2 mM .
Parsons
Sean P
SP
Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA. parsons_llabh@yahoo.co.uk
Sanders
Kenton M
KM
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000838:Anions / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D018118:Chloride Channels / Q000378:metabolism*; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits / Q000378:metabolism; D007583:Jejunum / Q000166:cytology / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018408:Patch-Clamp Techniques; D013997:Time Factors
D000838:Anions; D018118:Chloride Channels; D000255:Adenosine Triphosphate; D054751:Cyclic AMP-Dependent Protein Kinase Catalytic Subunits; D002118:Calcium