Figure 1.

Platelet aggregation induced by ADP and serotonin. Left panel: aggregation induced by 1 μM ADP + 1 μM buffer solution (plain Tyrode's solution (PT)). Right panel: aggregation induced by 1 μM ADP + 1 μM serotonin (5-HT). The ratio between the two highest light transmission percentages is the 5-HT-to-ADP response ratio (in the example, 68.5/21.2 = 3.23-fold increase).