Antithrombotic effects of sodium salt of 17(R)-methyl-20-isopropylidenecarbacyclin in the arteriole of the hamster cheek pouch.

Antithrombotic effects of sodium salt of 17(R)-methyl-20-isopropylidenecarbacyclin (CS-570), a chemically stable prostaglandin I2 (PGI2, epoprostenol, prostacyclin) derivative, were investigated in the arteriole of the hamster cheek pouch. A microthrombus was produced by a slight mechanical injury followed by iontophoretic application of adenosine diphosphate (ADP) to an arteriole of 70 to 100 micron in diameter. The platelet thrombus size was determined with a video image processor. With this technique, a reproducible and quantitatively measurable periodical thrombus was obtained. CS-570 inhibited the thrombus formation dose-dependently. The potency of CS-570 was about 1/8 that of PGI2 and 6 times that of carbacyclin when infused i.v. CS-570 also decomposed an established thrombus. Alprostadil (PGE1), dipyridamole and ticlopidine failed to show inhibitory effects. The antithrombotic effect of CS-570 was definitely demonstrated.