Effects of Protopine on Blood Aggregation; 1

Abstract

The effects of protopine on blood platelet aggregation were investigated in in vivo, ex vivo, and in vitro models. Protopine (0.25 mM/kg,p.o.) showed stronger inhibitory effects on endotoxin-induced disseminated intravascular coagulation (DIC) in rats and on pulmonary thromboembolism in mice compared with that of acetylsalicylic acid and dipyridamole (1.0 mM/kg, p.o., respectively), and also inhibited collagen- and ADP-induced rat ex vivo blood platelet aggregation. Protopine was found to intensify the inhibitory effect of PGI₂ on platelet aggregation, but there was no effect on PGI₂ generation from rat arterial tissue. Oral administration of acetylsalicylic acid (0.1 mM/kg) strongly inhibited the PGI₂ generation. These results suggest that protopine will be able to serve as an anti-thrombic agent without inhibitory effects of PGI₂ generation as observed with acetylsalicylic acid.