Effects of epinephrine on ADP-induced platelet aggregation. (A) Aggregation was induced by 0.5 μmol/L ADP alone (top) or the presence of 1 μmol/L epinephrine (bottom). (B) Aggregation induced by 0.5 μmol/L ADP was inhibited by 100 μmol/L A3P5P in the absence (top) or the presence (bottom) of 1 μmol/L epinephrine. (C) Effects of A3P5P on cAMP levels in the absence (top) or the presence (bottom) of 1 μmol/L epinephrine.