Outwardly rectifying chloride channels in lymphocytes.
Outwardly rectifying Cl- channels in cultured human Jurkat T-lymphocytes were activated by excising a patch of membrane using the inside-out (i/o) patch-clamp configuration and holding at depolarized voltages for prolonged periods of time (1-6 min at +80 mV, 20 degrees C). The single-channel current at +80 mV was 4.5 +/- 0.3 pA and at -80 mV, it was 1.0 +/- 0.4 pA. After activation, the probability of being open (Po) for the lymphocyte channel was voltage independent. Activation of the Cl- channel in lymphocytes was temperature dependent. Nineteen percent of i/o recordings from lymphocytes made at 20 degrees C exhibited Cl- channel activity. In contrast, 49% of recordings made at 30 degrees C showed channel activity. The number of channels in an active patch was not significantly different at the two temperatures. Channel activation in excised, depolarized patches also occurred 20-fold faster at 30 degrees C than at 20 degrees C. There was no marked change in the single-channel conductance at 30 degrees C. Open-channel conductance was blocked by 200 microM indanyloxyacetic acid (IAA) or 1 mM SITS when applied to the intracellular side of the patch. The characteristics of this channel are similar to epithelial outwardly rectifying Cl- channels thought to be involved in fluid secretion.
Garber
S S
SS
Department of Neurobiology, Stanford University, California 94305-5401.
D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000494:pharmacology; D018118:Chloride Channels; D002712:Chlorides / Q000097:blood*; D004594:Electrophysiology; D006801:Humans; D007189:Indans / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007945:Leukemia, Lymphoid; D008565:Membrane Proteins / Q000097:blood* / Q000187:drug effects; D012044:Regression Analysis; D013601:T-Lymphocytes / Q000378:metabolism*; D013696:Temperature; D014407:Tumor Cells, Cultured
D018118:Chloride Channels; D002712:Chlorides; D007189:Indans; D007473:Ion Channels; D008565:Membrane Proteins; C060056:indanoxyacetic acid 94; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid