Effect of adrenaline on thrombin and ADP-induced aggregation. The effect of adrenaline on ADP- and thrombin-induced aggregation in washed platelets prepared from normal (A) or patient (B) blood. Washed platelets were incubated with adrenaline (3 μM) or saline just prior to the addition of either ADP (5 μM) or thrombin (0.025 U/mL). In experiments with thrombin, a combination of creatinine phosphate (CP; 40 mM) and creatine phosphokinase (CPK; 100 U/mL) was added 1 minute prior to agonist addition. Arrows indicate points of induction. The results shown are representative of 2 other independent experiments.