Inhibition of arterial PGI2 generation and platelet aggregation by aspirin in rabbits ex vivo.
In 63 rabbits the generation of prostacyclin (PGI2) by coeliac and mesenteric arteries and arachidonate-induced platelet aggregation in platelet rich plasma (PRP) were studied at 24th, 48th and 72nd hour after oral administration of single doses of acetyl salicylic acid (ASA) (15, 25 and 50 mg/kg). Only at the lowest dose ASA caused a selective inhibition of platelet cyclo-oxygenase. ASA at this dose had a cumulative inhibitory effect on arterial cyclo-oxygenase when it was administered in an ineffective single daily dose during three days every 24h. It is concluded that in vivo ASA can be hardly considered as a preferential inhibitor of platelet cyclo-oxygenase.
D000818:Animals; D001158:Arteries / Q000187:drug effects; D001241:Aspirin / Q000494:pharmacology*; D011464:Epoprostenol / Q000096:biosynthesis* / Q000097:blood; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D010974:Platelet Aggregation / Q000187:drug effects*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011817:Rabbits
D011464:Epoprostenol; D011451:Prostaglandin-Endoperoxide Synthases; D001241:Aspirin