An experimental model for arterial
thrombosis has been investigated in rats. A loop of
polythene tubing inserted in the left carotid artery induced
thrombus formation on the arterial wall at the points of contact with the
tips of the
cannula. Sprague Dawley (CFY) rats were more susceptible to the thrombotic stimulus than were Wistar (WAG) rats. Whole blood platelet adhesiveness measured by a glass bead column method was higher in CFY rats than in WAG rats. 6-[p-(4-Phenylacetylpiperazin-1-yl)-phenyl]-4,5-dihydro-3(2H)-pyridazinone (
CCI 17810) inhibited
thrombus formation in CFY rats. Both the incidence of occlusion of the cannulated artery and the mean
thrombus weight were reduced by
CCI 17810 in doses of 25, 50 or 100 mg/kg administered orally twice daily; the effects were dose-related. The effects of
aspirin depended on the dose administered. A high dose (200 mg/kg) did not inhibit
thrombus formation whereas a low dose (20 mg/kg) reduced the incidence of occlusion and the mean
thrombus weight. These results are in accord with the differential effects of
aspirin on platelet and blood vessel wall
cyclooxygenase.