calcimycin and dauricine

The production of platelet activating factor (PAF) in bovine cerebral microvascular endothelial cells (CME cells) and the effects of tetrandrine (Tet) and dauricine (Dau) on the PAF production were investigated. PAF was determined by the aggregation of washed rabbit platelets. The results showed that the CME cells produced PAF 5.93 ng/8.5x 10(5) cells under the calcimycin 2.5 mumol.L-1 stimulation. Tet and Dau 1, 10, and 100 mumol.L-1 inhibited the production of PAF by 18.2%, 51.8%, 56.8%, and 26.3%, 63.3%, 65.9%, respectively. Tet concentration-dependently inhibited the PAF 9.1 nmol.L-1 induced washed rabbit platelets aggregation with the IC50 of 3.05 mumol.L-1 (95% confidence limits: 0.59-15.86 mumol.L-1). The binding of [3H]triazolodiazepine to the CME cells was partially displaced by Tet 0.02-33.00 mumol.L-1. It is suggested that the cerebrovascular system produces PAF at the pathological conditions and the inhibition of Tet and Dau.

Topics: Alkaloids; Animals; Benzylisoquinolines; Brain; Calcimycin; Cattle; Cells, Cultured; Endothelium, Vascular; Isoquinolines; Microcirculation; Platelet Activating Factor; Platelet Aggregation; Platelet Aggregation Inhibitors; Rabbits; Tetrahydroisoquinolines

The effects of dauricine (Dau) on the release of platelet activating factor (PAF) from mouse peritoneal macrophages stimulated by calcimycin (A-23187) was studied. The method of sodium [3H]acetate incorporating into macrophages to synthesize PAF was set up for the first time. Calcimycin (0.2 mumol/L) significantly induced mouse peritoneal macrophages to utilize sodium [3H]acetate to synthesize PAF. PAF released from macrophages medium fluid increased as the concentration of sodium [3H]acetate increased. The maximal amount of PAF released from macrophages was attained by incubating macrophages with sodium [3H]acetate (250 mumol/L) and calcimycin (2 mumol/L) over 30 min. Extracted by CHCl3:CH3OH:H2O (2:2:1.8), separated by thin layer chromatography (TLC) and determined by liquid scintillation counting, PAF released was inhibited significantly by Dau both in time (10-30 min) and dose (1-1000 mumol/L) dependent manners. The IC50 of Dau for the formation of PAF was 2.5 mumol/L. On the same condition PAF release was also significantly inhibited by quinacrine at 500 mumol/L. The results indicate that Dau is a potent inhibitor of PAF synthesis in mouse peritoneal macrophages.

Topics: Alkaloids; Animals; Benzylisoquinolines; Calcimycin; Dose-Response Relationship, Drug; Female; Isoquinolines; Macrophages; Male; Mice; Peritoneal Cavity; Platelet Activating Factor; Platelet Aggregation Inhibitors; Tetrahydroisoquinolines