Effect of NSC23766 on aggregation of platelets in blood and PRP stimulated with ADP. (A) Blood (with or without aspirin) or (B) PRP (with or without aspirin) was pre-treated with 300 μM NSC23766 for 5 min whilst stirring at 37°C before stimulation with ADP (5 μM). Aggregation values of PRP are % of maximal aggregation induced by collagen (5 μg/ml). Values are mean ± SD (n = 4). * p < 0.05.