Effect of dipfluzine on platelet aggregation and thrombus formation.

Dipfluzine (Dip) is a novel diphenylpiperazine calcium channel blocker first synthesized in China. Effects of Dip on experimental thrombosis and platelet aggregation were studied in vitro and in vivo compared with cinnarizine (Cin). Dip 1 and 2 mg.kg-1 i.v. and incubated in 1-100 mumol.L-1 in vitro inhibited dose- or concentration-dependent rabbit platelet aggregation induced by ADP and by arachidonic acid (AA), respectively. Dip 2.5-10 mg.kg-1 i.v. and 50-100 mg.kg-1 ip inhibited the thrombosis in rats. Dip 10 mg.kg-1 i.v. and 200 mumol.L-1 depressed the in vitro thrombosis. These results suggest that attenuation of disturbed platelet-vessel wall reaction associated with platelet activation and vasoconstriction may be a main factor involved in the antithrombotic action of Dip, and that the effects of Dip were more potent than those of Cin.