title: The platelet-activating factor receptor antagonist L-659,989 inhibits phospholipase D activity.
abstract: The platelet-activating factor (PAF) receptor antagonist L-659,989 [(+/-)-trans-2-(3-methoxy-5-methylsulfonyl-4-propoxyphenyl)-5-(3,4, 5-trimethoxyphenyl)tetrahydrofuran)] has been reported to be a specific inhibitor of the PAF receptor and as such, it is widely used for assessment of PAF receptor mediated biological effects. We report here that L-659,989 may not be as specific as previously reported because it is also a potent inhibitor of phospholipase D activity. At concentrations of 30 micrograms/ml, L-659,989 inhibited basal and agonist-stimulated phospholipase D activity by about 55% and 70-100% respectively, through a mechanism that may involve the generation of intracellular ceramides. Another PAF receptor antagonist, WEB-2086, did not affect phospholipase D activity at concentrations up to 50 micrograms/ml. Either of these inhibitors when present at 20 micrograms/ml are reported to fully block the effects of PAF. Furthermore, L-659,989 directly inhibited the activity of bacterial PLD in vitro. These results indicate that caution is required in the interpretation of results derived from the use of L-659,989.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005663:Furans / Q000494:pharmacology*; D008077:Lipoproteins, LDL; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D010739:Phospholipase D / Q000037:antagonists & inhibitors* / Q000302:isolation & purification; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors*; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled