Single potassium channels blocked by lidocaine and quinidine in isolated turtle colon epithelial cells.
The patch-clamp technique for recording single-channel currents across cell membranes was applied to single turtle colon epithelial cells isolated with hyaluronidase. With electrodes fabricated from Corning #7052 glass, high-resistance seals were consistently formed to these cells. In on-cell patches with low K (2.5 mM) in the pipette and high K (114.5 mM) in the bath, outward K currents were recorded that had a slope conductance of 17 pS and a reversal potential greater than -70 mV. Currents through this K channel were blocked by lidocaine, quinidine, and barium. These agents also block a cell swelling-induced K conductance identified by macroscopic current measurements in the basolateral membranes of the intact colonic epithelium, suggesting that the 17 pS K channel identified by single-channel recording in isolated turtle colon cells may be responsible for this macroscopically defined K conductance.
D000818:Animals; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology*; D004847:Epithelial Cells; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism; D008012:Lidocaine / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D011802:Quinidine / Q000494:pharmacology*; D014426:Turtles / Q000378:metabolism*
D007473:Ion Channels; D008012:Lidocaine; D011802:Quinidine; D011188:Potassium