AIM To establish radioligand binding assay of PAF (platelet activating factor) receptors in mouse peritoneal macrophages and observe the characteristics of PAF receptors. METHODS PAF receptor radioligand binding was studied in intact adherent mouse peritoneal macrophages by -PAF. The radioactivity was counted with an LS6500 scintillation system. RESULTS The PAF receptor binding was shown to be saturable with an equilibrium K D of 3.2 nmol?L -1 and a B max of 100.2 fmol?1?10 6 cells -1. The competitive analysis showed that such specific binding could be inhibited by BN52021. CONCLUSION Utilizing the adherent character of macrophages, the binding ligands could be separated from non-binding ligands without negative pressure filtration, then cells could reserve fine activity, and PAF receptors could be near to physiological properties for screening of PAF antagonist.

Aim To study the inhibitory effect of ginkgolide B (BN52021) on the PAF induced changes of chemotaxis of murine peritoneal macrophages and the related polymerization of F-actin.Methods Chemotaxis assays were performed using a modified 48-well Boyden chamber. Actin polymerization of murine peritoneal macrophages was analyzed by flow cytometry using a specific fluorescent stain. Results Peritoneal macrophages significantly migrated toward platelet-activating factor(PAF) through a micropore filter; however, in the presence of PAF receptor antagonist BN52021 (0. 01the actin polymerization of murine peritoneal macrophages induced by PAF in the presence of Ca2+ , but not in Ca2+ -free medium. Conclusion The results suggested that preventing polymerization of F-actin may be a pathway by BN52021 to inhibit the chemotaxis of macrophages, and this effect seems to be Ca2+dependent. The data further indicated that inhibition of PAF induced macrophage chemotaxis is an important mechanism underlying the anti-inflammatory action of BN52021.

Objective To investigate the glycosidic linkage and immunomodulating activities of crude polysaccharides from the seeds of Zea mays. Methods Extraction, isolation and purification of polysaccharides were carried out with boiling-water extraction plus resolving deposit repeatedly. The structure was elucidated on basis of physicochemical properties and spectral data, and the biological activities were evaluated by means of Immunopharmacological examination. Results The structure of polysaccharides from the seeds of Z. mays exhibited identical structure with rice bran polysaccharides, i.e., a kind of glucan withα-1,4 andα-1,6 glucosidic bonds as the main frame. Conclusion Polysaccharides was obtained from the seeds of Z. mays for the first time, and it showed significant immunomodulating activity in mice.

This study is to explore the effect of ginkgolide B (BN52021) on the production of nitric oxide (NO), interleukin (IL)-6 and regulated upon activation normal T cell expressed and secreted (RANTES) from astrocytes induced by stimulators. Primary cultured rat astrocytes were stimulated with lipopolysaccharides (LPS), the production of NO was assayed using Griess reaction; U251 cells were stimulated with IL-1 beta, the contents of IL-6 and RANTES in the supernatant were measured using ELISA. The mRNA expressions of IL-6 and RANTES were detected using RT-PCR. LPS (10 ng mL(-1) to 10 microg mL(-1)) could stimulate rat astrocytes to produce NO in a dose-dependent manner. Ginkgolide B at the concentrations of 0.1-10 micromol L(-1) were shown to decrease NO production significantly. IL-1 beta could induce the mRNA expression and protein secretion of IL-6 from U251 cells, as well as RANTES. Ginkgolide B at concentrations of 0.1-10 micromol L(-1) were shown to inhibit RANTES secretion, and to inhibit mRNA expression of IL-6 and RANTES at concentration of 10 micromol L(-1). Ginkgolide B has inhibitory effect on the production of NO, IL-6 and RANTES from astrocytes treated with inflammatory stimulators.