Figure 4.

Role of cPLA₂α in platelet spreading on fibrinogen. Washed platelets were allowed to adhere to fibrinogen-coated slides for 30 minutes at 37°C in the presence or absence of 20 μM of ADP, 10 μg/mL of CRP, or 1 mM of PAR4 receptor-activating peptide. (A) Platelets were stained with anti-pTyr antibody (green) and rhodamine-phalloidin (red). Images were captured on a deconvolution microscope equipped with a 100× objective. Each panel is representative of 3 separate experiments. Bar represents 10 μm. (B) Pyrrophenone was used at a concentration of 50 μM. (C) SQ29 548 was used at a concentration of 10 μM. In panels B and C, platelets were stained with anti-β3 antibody and rhodamine-phalloidin. Images were captured on an Olympus T-2000 microscope, and platelet surface areas were quantified by computerized image analysis. Data are mean plus or minus SEM of at least 100 platelets per treatment condition.