title: Desensitization and antagonism of rat polymorphonuclear leukocytes stimulated with PAF acether.
abstract: The activation of rat polymorphonuclear leukocytes (PMN) with PAF-acether (platelet-activating factor) was blocked by two antagonists: 48740 RP and BN 52021. The release of beta glucuronidase was usually better inhibited than that of lysozyme suggesting that the tested antagonists interfere rather with PAF-acether exocytosis of azurophil granules. Inhibition was relatively specific, even though a moderate effect (below 34%) upon PMN activation by the two unrelated agonist n-formyl-Methionyl-Leucyl-Phenylalanine (fMLP) and leukotriene B4 sometimes reached significance. The partial persistence of inhibition to stimulation with PAF-acether after elimination of both inhibitors suggests that they do not act at the PAF-acether receptor only. Furthermore, the observation of cross desensitization between PAF-acether and fMLP may be related to common pathways and/or metabolites, including PAF-acether itself.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003571:Cytochalasin B / Q000494:pharmacology; D004224:Diterpenes; D005089:Exocytosis / Q000187:drug effects; D046934:Ginkgolides; D005966:Glucuronidase / Q000097:blood; D007783:Lactones; D007975:Leukotriene B4 / Q000494:pharmacology; D008297:Male; D009113:Muramidase / Q000097:blood; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000201:enzymology / Q000502:physiology*; D010936:Plant Extracts / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D004224:Diterpenes; D046934:Ginkgolides; D007783:Lactones; D010936:Plant Extracts; D010972:Platelet Activating Factor; D011725:Pyridines; D013844:Thiazoles; D007975:Leukotriene B4; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; C052520:3-(3-pyridinyl)-1H,3H-pyrrolo(1,2-c)thiazole-7-carboxamide; C045856:ginkgolide B; D009113:Muramidase; D005966:Glucuronidase