1974 年 94 巻 2 号 p. 204-214
Since 2-(9-oxo-xanthen-2-yl)-propionic acid (Y-5554) was found to possess anti-inflammatory properties, some experiments were carried out on its activities on platelets which were obtained from rabbits, rats, and guinea-pigs. Y-5554 inhibited the collagen- and thrombin-induced platelet aggregation in platelet-rich plasma (PRP) of rabbits, rats, and guinea-pigs in vitro. This compound also inhibited the adenosine diphosphate (ADP)-induced second-phase aggregation in PRP of guinea-pigs. It also inhibited the thrombin-induced release reaction in the washed platelet suspension obtained from the animals. Y-5554 inhibited the collagen- and ADP·collagen-induced platelet aggregation in vitro, in guinea-pigs by oral administration. These inhibitory activities were found to be affected by the difference of aminal species. The inhibitory properties of Y-5554 were found to be similar to those of phenylbutazone ; Y-5554 was more active than acetylsalicylic acid and less active than indomethacin. These findings show that the inhibitory activities of Y-5554 on the platelet aggregation may be due to its protective properties on platelets. This suggests that Y-5554 may be useful for the treatment of patients with elevated platelet aggregation.