Abstract |
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.
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Authors | G F Labrecque, D Holowka, B Baird |
Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 266
Issue 23
Pg. 14912-7
(Aug 15 1991)
ISSN: 0021-9258 [Print] United States |
PMID | 1831198
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Antigens, Differentiation, B-Lymphocyte
- Receptors, Fc
- Receptors, IgE
- Virulence Factors, Bordetella
- Colforsin
- Immunoglobulin E
- Carbonyl Cyanide m-Chlorophenyl Hydrazone
- Ionomycin
- Cholera Toxin
- Pertussis Toxin
- Quinidine
- Rubidium
- Potassium
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Topics |
- Animals
- Antigens, Differentiation, B-Lymphocyte
(metabolism)
- Basophils
(metabolism)
- Biological Transport
(drug effects)
- Carbonyl Cyanide m-Chlorophenyl Hydrazone
(pharmacology)
- Cell Membrane Permeability
(drug effects)
- Cholera Toxin
(pharmacology)
- Colforsin
(pharmacology)
- Immunoglobulin E
(metabolism)
- Ionomycin
(pharmacology)
- Leukemia, Experimental
- Pertussis Toxin
- Potassium
(metabolism)
- Quinidine
(pharmacology)
- Rats
- Receptors, Fc
(metabolism)
- Receptors, IgE
- Rubidium
(metabolism)
- Tumor Cells, Cultured
- Virulence Factors, Bordetella
(pharmacology)
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