1983 年 11 巻 2 号 p. 239-250
We have studied the effects of polyunsaturated fatty acids on platelet aggregation, mainly by means of the in vitro experiments. The results of the studies are as follows.
1) It seemed that arachidonic acid aggregated platelets as well irrespective of prostaglandin pathways.
2) Eicosapentaenoic acid (EPA) inhibited platelet aggregation caused by various aggregating agents, such as ADP, collagen, and arachidonic acid, when platelet-rich plasma was used. However, EPA itself aggregated platelets when washed platelets were used.
3) On the other hand, such a low concentration of EPA as not to induce platelet aggregation by itself, inhibited platelet aggregation caused by arachidonic acid, even when washed platelets were used.
4) From these results it was thought that the inhibitory effect of EPA on platelet aggregation was not active and direct one but indirect due to reducing the use of arachidonic acid in the platelets.
5) It was suggested that the ratio of EPA to arachidonic acid in phospholipid fatty acids of platelets needed to be more than 0.14, in order that EPA had an inhibitory effect on platelet aggregation.
6) It is considered that the optimum balance between ω-3 species of fatty acids and ω-6 ones in phosphlipid fatty acids of platelets is necessary for platelets to function normally.