The effect of non-steroid anti-inflammatory drugs, dibutyryl cyclic 3',5'-adenosine monophosphate and phosphodiesterase inhibitors on platelet aggregation and the platelet release reaction in normal and essential fatty acid deficient rats.

A comparison was made of the action of three classes of substances with platelet aggregation inhibiting effect in normal and essential fatty acid deficient rats. In the latter group, the effect of indomethacin was considerably reduced, whereas the difference was smaller with aspirin. Dibutyryl cyclic AMP had the same inhibiting effect in both groups. Of the phosphodiesterase inhibitors tested, dipyridamole was inactive, whereas the inhibiting effects of caffeine and papaverine are slightly reduced in the deficient animals. The same differences between the two groups were seen in the magnitude of the release reaction after 14C-serotonin labelling. These data support the idea that the non-steroid anti-inflammatory drugs act by inhibiting the formation of an aggregation-inducing substance from arachidonic acid.