Characterization of increased K+ permeability associated with the stimulation of receptors for immunoglobulin E on rat basophilic leukemia cells.
Aggregation of immunoglobulin E-receptor complexes on the surface of rat basophilic leukemia cells stimulates an increase in plasma membrane K+ permeability that is monitored as an increase in the rate of efflux of preloaded 86Rb+. A major component of this stimulated 86Rb+ efflux appears to be due to a Ca(2+)-activated K+ channel because it is inhibited by quinidine in parallel with the inhibition of degranulation and membrane potential repolarization, it is blocked by 0.1 mM La3+, and it is dependent on external Ca2+. Depolarization of the plasma membrane by carbonyl cyanide 3-chlorophenylhydrazone inhibits stimulated Ca2+ influx and prevents antigen-induced 86Rb+ efflux, and increased external Ca2+ partially restores 86Rb+ efflux under these conditions. In addition, potentiation of antigen-stimulated Ca2+ influx by pretreatment with cholera toxin increases the initial rate of stimulated 86Rb+ efflux. Another component of antigen-stimulated K+ efflux appears to be mediated by a guanine nucleotide-binding protein because pretreatment of rat basophilic leukemia cells with pertussis toxin decreases the initial rate of antigen-stimulated 86Rb+ efflux to 40% of that for the untreated cells. Stimulated 86Rb+ efflux is also observed when ionomycin is used to increase cytoplasmic Ca2+ and to trigger membrane depolarization. The efflux stimulated by ionomycin is inhibited by quinidine but not by pertussis toxin pretreatment; thus, it appears to occur through the Ca(2+)-activated K+ efflux pathway. It is proposed that these K+ efflux pathways serve to sustain the Ca2+ influx that is necessary for receptor-mediated triggering of cellular degranulation.
Labrecque
G F
GF
Department of Chemistry, Cornell University, Ithaca, New York 14853.
Holowka
D
D
Baird
B
B
D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D001491:Basophils / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D007073:Immunoglobulin E / Q000378:metabolism*; D015759:Ionomycin / Q000494:pharmacology; D007942:Leukemia, Experimental; D037342:Pertussis Toxin; D011188:Potassium / Q000378:metabolism*; D011802:Quinidine / Q000494:pharmacology; D051381:Rats; D011961:Receptors, Fc / Q000378:metabolism*; D017455:Receptors, IgE; D012413:Rubidium / Q000378:metabolism; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000944:Antigens, Differentiation, B-Lymphocyte; D011961:Receptors, Fc; D017455:Receptors, IgE; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D007073:Immunoglobulin E; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D015759:Ionomycin; D002772:Cholera Toxin; D037342:Pertussis Toxin; D011802:Quinidine; D012413:Rubidium; D011188:Potassium