Figure 5.

Regulatory effects of antagonists of collagen receptors in brazilin-mediated phospholipase C (PLC)γ2 and Lyn phosphorylation of washed platelets. Washed platelets (1.2 × 10⁹/ml) were preincubated with JAQ1 (4 μg/ml) or Sam.G4 (4 μg/ml), followed by the addition of (A, C-D) brazilin (50 μΜ) or (B-C) thrombin (0.5 U/ml), collagen (1 μg/ml), ADP (20 μΜ to trigger platelet activation. The reactions were stopped by the addition of EDTA (10 mM). Cells were then collected and subcellular extracts were analyzed for (A-B) PLCγ2 and (C-D) Lyn phosphorylation by immunoblotting, as described in the “Materials and methods” section. Profiles (A to D) are representative examples of 4 similar experiments. Data are presented as the means ± S.E.M. (n=4); ^*p<0.05 and ^**p<0.01, compared to the solvent (0.5% DMSO)- or thrombin-treated group; ^#p<0.05 and ^##p<0.01, compared to the brazilin-treated group.