Fig. 4. Platelet aggregation. Washed platelets (3.0 × 10⁸ platelets mL⁻¹), pre-incubated at 37 °C in the presence of saline (line 1, red), 10 μM GAD (line 2, green) or 100 μM GA (line 3, blue), were stimulated with thrombin (a) or collagen (b) as indicated. Platelet aggregation was monitored as described in the Methods section and quantified by the light transmission reaching within 6 min. Tracings are representative of at least six independent experiments.