Effects of cadmium on potassium currents in activated B lymphocytes.
We have applied the patch clamp technique in the whole-cell configuration to study whole-cell currents in B lymphocytes under three conditions: (i) resting; (ii) interleukin-4 (IL-4)-treated; and (iii) IL-4 plus cadmium-treated murine B lymphocytes. Through these experiments we have: (i) confirmed our earlier findings and the observation of others that resting B cells express only outward currents; (ii) confirmed the presence of an inwardly rectifying K+ current elicited by treatment with the lymphokine IL-4 that was revealed in our previous study on single channel currents; (iii) demonstrated that both inward and outward rectifying K+ currents in IL-4-treated B cells are dramatically reduced by exposure to 20 microM cadmium; and (iv) determined that the activation curve of the IL-4-induced inward rectifier is shifted to more negative voltages by cadmium. We propose that one of the mechanisms by which cadmium can mediate toxicity in activated B lymphocytes is through the suppression and modulation of potassium currents, effects that may alter the timing of entry into the cell cycle.
McCarthy
D C
DC
Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756.
Noelle
R J
RJ
Gallagher
J D
JD
McCann
F V
FV
D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D002104:Cadmium / Q000494:pharmacology*; D066298:In Vitro Techniques; D015847:Interleukin-4 / Q000494:pharmacology; D008213:Lymphocyte Activation; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D013154:Spleen / Q000502:physiology
D015221:Potassium Channels; D002104:Cadmium; D015847:Interleukin-4