title: Retinoic acid blocks potassium channels in human lymphocytes.
abstract: Using the whole-cell variation of the patch-clamp technique, we have determined that retinoic acid, an active metabolite of natural vitamin A that possesses potent immunomodulating activity, reduces the K+ current in human T lymphocytes and natural killer cells in a dose-dependent manner: acute treatment with 5 X 10(-5) M caused over a 70% reduction while concentrations less than 1 X 10(-5) M caused less than 30% inhibition. Natural killer activity and T cell mitogenesis was inhibited by RA at concentrations that reduced the K+ conductance and correlated with the ability of a variety of classical ion-channel blockers to inhibit the functional activity of these cells. Thus, the reported inhibitory effects on natural killer activity and T cell mitogenesis by high concentrations of retinoic acid can be explained by its effect on the K channel.
mesh_terms: D002469:Cell Separation; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D011188:Potassium / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D007473:Ion Channels; D014212:Tretinoin; D011188:Potassium