title: Single channel recordings of calcium-activated potassium channels in the apical membrane of rabbit cortical collecting tubules.
abstract: Recordings of single potassium channels from the apical membrane of rabbit cortical collecting tubule have been achieved using the patch-clamp technique. The conductive properties of the channel have been studied in inside-out patches. The slope conductance of the open channel is approximately equal to 90 pS. The channel is selective to potassium over sodium, with a selectivity ratio of 9:1. Decreasing the calcium concentration of the solution bathing the cytoplasmic face of the patch results in a decrease of the open-channel probability. Decreasing the calcium concentration to 10 nM or less completely inhibited channel activity. The channel is also inhibited by barium in a dose-dependent fashion.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004553:Electric Conductivity / Q000187:drug effects; D005260:Female; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D007672:Kidney Cortex / Q000502:physiology*; D007684:Kidney Tubules / Q000502:physiology*; D007700:Kinetics; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits
chemical_list: D007473:Ion Channels; D011188:Potassium; D002118:Calcium