Abstract: The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol/L, 100 mmol/L) or verapamil (10 mmol/L, 100 mmol/L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol/L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A-23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.

Key words: Berbamine, Verapamil, Platelet activating factor (PAF), Neutrophils, Human, Platelet aggregation