title: Leukotriene D4 induced calcium changes in U937 cells may utilize mechanisms additional to inositol phosphate production that are pertussis toxin insensitive but are blocked by phorbol myristate acetate.
abstract: DMSO differentiated U937 cells responded to 10(-6) M LTD4, LTB4 and FMLP with an increase in both InsP formation and [Ca2+]i. FMLP caused a greater rise in InsPs than either LTD4 or LTB4, which were equivalent. LTD4, however, caused a greater increase in [Ca2+]i than LTB4 (4-fold) or FMLP. The FMLP [Ca2+]i and InsP responses were abolished by pertussis toxin (100 ng/ml for 4 h) but were unaffected by PMA (10(-7) M for 3 min). In contrast, the LTD4 [Ca2+]i and InsP responses were reduced by only 50% by pertussis toxin, whilst PMA reduced the [Ca2+]i and InsP responses to LTD4 by 75 and 30%, respectively. These results suggest that mechanisms additional to InsP formation exist for mediating LTD4 evoked increases in [Ca2+]i.
authors.affiliation: Bioscience II, ICI Pharmaceuticals, Mereside, Alderley Park, Cheshire, U.K.
authors.forename: K
authors.initials: K
authors.lastname: Pollock
authors.forename: J
authors.initials: J
authors.lastname: Creba
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D007295:Inositol Phosphates / Q000096:biosynthesis*; D007975:Leukotriene B4 / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D037342:Pertussis Toxin; D013189:SRS-A / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
chemical_list: D007295:Inositol Phosphates; D013189:SRS-A; D010566:Virulence Factors, Bordetella; D007975:Leukotriene B4; D009240:N-Formylmethionine Leucyl-Phenylalanine; D037342:Pertussis Toxin; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium