lignans and 14-deoxyandrographolide

To identify and characterize a platelet activating factor (PAF) receptor in bovine neutrophils by use of radioligand binding, reverse transcription-polymerase chain reaction (RT-PCR) assay, and western blot analysis.. 4 healthy adult cows.. Bovine neutrophil membranes were isolated for association, dissociation, and saturation binding experiments with PAF labeled with hydrogen 3 (3H-PAF). The RT-PCR assay was performed with appropriate human primers, and western blot analysis was developed with a polyclonal antibody obtained from a peptide of bovine PAF receptor.. Analysis of kinetic binding data supported a single class of PAF receptor. Binding of 3H-PAF to membrane preparations was selectively displaced by PAF and a nonhydrolyzable analogue of guanine triphosphate (Gpp[NH]p) and by lyso-PAF (a biologically inactive analogue of PAF) to a lesser extent. Among other PAF receptor antagonists, 14-deoxyandrographolide and WEB 2086 were the most effective in inhibiting 3H-PAF binding sites in neutrophil membranes; 2 lignans, schisandrin-A and gamma-schisandrin were also effective, but 2 gingkolides (BN52020 and BN52021) only mildly inhibited 3H-PAF binding. Results of RT-PCR assay and western blot analysis of neutrophil crude membranes confirmed the presence of a PAF receptor.. Results indicated that bovine neutrophils express only 1 type of PAF receptor, and it is likely that this receptor is involved in inflammatory responses. The most effective PAF antagonists were 14-deoxyandrographolide and WEB 2086; these PAF antagonists may be potentially useful in the treatment of inflammatory processes in cattle.

Topics: Animals; Azepines; Base Sequence; Blotting, Western; Cattle; Cyclooctanes; Diterpenes; DNA Primers; DNA, Complementary; Enzyme-Linked Immunosorbent Assay; Ginkgolides; HL-60 Cells; Humans; Kinetics; Lactones; Lignans; Molecular Sequence Data; Neutrophils; Platelet Activating Factor; Platelet Membrane Glycoproteins; Polycyclic Compounds; Radioligand Assay; Receptors, G-Protein-Coupled; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Triazoles; Tritium