A study of intravascular platelet aggregation by continuous platelet counting

Abstract Intravascular platelet aggregation has been studied by measuring the response to aggregating agents using continuous platelet counting. Dose-dependent falls in platelet count occurred after the injection of collagen, prostaglandin H 2 (PGH 2 ), arachidonic acid (AA) and four synthetic prostanoids in rats. Indomethacin partially inhibited collagen- and AA-induced aggregation in the rat and collagen-induced aggregation in the rabbit. Indomethacin and aspirin did not produce a dose-dependent inhibition of collagen-induced aggregation over the range of doses tested. 1-n-butylimidazole inhibited collagen- and PGH 2 -induced aggregation in the rabbit but did not inhibit collagen- or AA-induced aggregation in the rat.