OBJECTIVETo investigate the antithrombotic effects and its molecular mechanisms of prazosin combined with anisodamine (Ani).

METHODSIsolated rat tail artery rings model was employed to evaluate the vasodilative effects of drugs, mice tail thrombosis model induced by carrageenan was used to study the antithrombotic effects and its molecular mechanisms of the drug composition.

RESULTSAmong alpha1-adrenoreceptor antagonists, prazosin(Pra) had the greatest relaxation rate, which was (82.6 +/- 8.9)%, and the EC50 value was 0.44 micromol/L. The drug composition of anisodamine and prazosin of different doses could decrease the length of the tail thrombosis from (24.6 +/- 4.6)mm to (6.9 +/- 2.7)mm, and the rate of thrombosis was decreased from 86.6% to 50.0%. The drug composition could prolong the prothrombin time (PT) distinctively, but it had no effect on the activated partial thromboplastin time (APTT). It also could restrain the decrease of serum levels of tissue plasminogen activator (t-PA) and 6- Keto -PGF1alpha as well as the increase of type-1 plasminogen activator inhibitor (PAI-1) and thromboxane B2 (TXB2) in the mice.

CONCLUSIONThe drug composition formed by anisodamine and prazosin has good effects of relaxing extremities tiny blood vessels and it can fight against thrombosis, its antithrombotic mechanisms may be related to the influence of the extrinsic coagulation pathway, inhibition of platelet activation functions and the promotion of fibrinolysis function.