Release of serotonin from RBL-2H3 cells by the Escherichia coli peptide toxin STb.
Heat-stable enterotoxin b (STb) of Escherichia coli is a 48-amino acid basic, disulfide-bonded peptide that causes intestinal secretion in experimental animal models. Recent evidence suggests that the in vivo mechanism of STb action involves release of 5-hydroxytryptamine (5-HT) and production of prostaglandin E2 (PGE2). Here we show STb-mediated release of 5-HT from rat basophilic leukemic cells (RBL-2H3), a mast cell line model used extensively to study 5-HT release. Increasing concentrations of biologically active STb resulted in a dose-dependent release of 5-HT from RBL-2H3 cells. In contrast to these results, reduced and alkylated STb had no effect on 5-HT release. Release of 5-HT from RBL-2H3 cells was independent of extracellular calcium ions and did not involve changes in the intracellular concentration of free Ca2+. In addition, pertussis toxin treatment completely blocked 5-HT release, indicating a role for a pertussis toxin-sensitive G-protein in the mechanism of 5-HT release from this cell type.
Harville
B A
BA
Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City 64110, USA.
Dreyfus
L A
LA
D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology*; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004768:Enterotoxins / Q000494:pharmacology*; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins; D005089:Exocytosis; D019204:GTP-Binding Proteins / Q000378:metabolism; D008407:Mast Cells / Q000187:drug effects*; D037342:Pertussis Toxin; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D010566:Virulence Factors, Bordetella; C034151:heat stable toxin (E coli); D012701:Serotonin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium