title: IgE-dependent activation of mast cells is not associated with enhanced phospholipid methylation.
abstract: Enhanced phospholipid methylation has been suggested to be an obligatory event in activation-secretion coupling in mast cells. However, we have consistently failed to demonstrate increased [3H]methyl incorporation into either whole-lipid extracts or separated lipids to accompany IgE-dependent induction of histamine release from rat peritoneal mast cells despite variation of the experimental protocol, animals and animal diet. Although the presence of 3-deazaadenosine and homocysteine thiolactone reduced IgE-dependent histamine release, treatment with these compounds elevated mast cell cyclic AMP levels. We conclude that IgE-dependent activation of mast cells is not associated with enhanced phospholipid methylation and that inhibition of histamine release by methylation inhibitors may be due to other effects of the drugs.
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000032:analysis; D006636:Histamine Release / Q000187:drug effects; D006710:Homocysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D007073:Immunoglobulin E / Q000276:immunology*; D066298:In Vitro Techniques; D008297:Male; D008407:Mast Cells / Q000276:immunology / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D008745:Methylation; D010718:Phosphatidylserines / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012436:S-Adenosylmethionine / Q000378:metabolism; D014316:Tritium; D014372:Tubercidin / Q000494:pharmacology
chemical_list: D010718:Phosphatidylserines; D010743:Phospholipids; C018258:3-deazaadenosine; D006710:Homocysteine; D014316:Tritium; D007073:Immunoglobulin E; D012436:S-Adenosylmethionine; D008715:Methionine; C007957:homocysteine thiolactone; D000242:Cyclic AMP; D014372:Tubercidin