Effects of internal chloride on ATP-sensitive K-channels in mouse pancreatic beta-cells.
The effect of internal Cl- on the K-ATP channel of pancreatic beta-cells was examined. Reducing Cl- from 140mM to 14mM potentiated channel activity (NPO) approximately 4.5 fold in 60% of patches but was without effect in 40% of patches. The Ki for channel inhibition by ATP was not changed. The inhibitory effect of Cl- interacted with the stimulatory action of MgGDP. In 140mM Cl-, 1mM MgGDP increased NPO in Cl(-)-sensitive patches only: when NPO was potentiated by 14mM Cl-, no further increase was produced by MgGDP. These observations suggest that MgGDP and low Cl- solution may increase channel activity via a similar mechanism.
University Laboratory of Physiology, Oxford, UK.
M
M
Takano
F M
FM
Ashcroft
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008564:Membrane Potentials; D051379:Mice; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects* / Q000378:metabolism
D002712:Chlorides; D015221:Potassium Channels; D000255:Adenosine Triphosphate