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.
Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756.
D C
DC
McCarthy
R J
RJ
Noelle
J D
JD
Gallagher
F V
FV
McCann
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