Functional roles of ion channels in lymphocytes.
The application of patch-clamp and video-imaging techniques has enabled responses of lymphocytes to be examined at the level of individual cells. Eight distinct types of ion channel activity have been revealed in T lymphocytes. A variety of external stimuli shifts the pattern of channel activity from the resting state, which is dominated by voltage-gated K+ channels. Channel regulation is achieved both by acute modulation and by altered expression in the membrane. During mitogen stimulation, Ca2+ channels and Ca(2+)-activated K+ channels become active and appear to underlie Ca2+ oscillations. These acute changes are followed by increased expression of voltage-gated K+ channels. In response to osmotic challenge in hypotonic media, cell swelling initiates activation of Cl- channels, which may, in turn, indirectly activate K+ channels and trigger a regulatory decrease in cell volume.
Cahalan
M D
MD
Department of Physiology and Biophysics, University of California, Irvine 92717.
Lewis
R S
RS
D000818:Animals; D015220:Calcium Channels / Q000502:physiology; D002713:Chlorine / Q000378:metabolism; D004594:Electrophysiology; D006801:Humans; D007473:Ion Channels / Q000502:physiology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D015221:Potassium Channels / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D014882:Water-Electrolyte Balance
D015220:Calcium Channels; D007473:Ion Channels; D015221:Potassium Channels; D002713:Chlorine