Effect of various antiplatelet agents on acute arterial thrombosis in the rat

Electrical stimulation of the rat carotid artery causes a deep medial injury and the formation of a platelet-rich thrombus. Occlusive thrombosis at sites of vessel wall injury was significantly reduced after the oral administration of clopidogrel, a potent analogue of ticlopidine, which showed dose-dependent inhibition of the thrombus formation (ED 50 =1.0±0.2 mg/kg, p. o.). Accumulation of thrombotic material was also considerably reduced after the i. v. administration of SR 27417, a highly potent and selective platelet activating factor receptor antagonist (ED 50 =10 μg/kg, i.v.), nafagrel, a thromboxane A 2 synthetase inhibitor (ED 50 =1.3 mg/kg, i. v.) and hirudin (ED 50 =140 μg/ kg, i. v.)