Effect of ethanol on platelet phospholipase A2

Platelet aggregation is known to be inhibited by ethanol, and this has been suggested to be one of the attenuating effects of ethanol in cardiovascular disease. Recent studies have implicated an inhibition of phospholipase A2 induced arachidonic acid release, since the production of prostanoids that are formed from arachidonic acid and are involved in the aggregation process has been shown to be diminished by ethanol. Phospholipase A2 is found in platelets in both a cytosolic form, from where it may translocate to the plasma membrane to release arachidonic acid, and in a secretory form which is released extracellularly upon activation. In the present study, the effect of ethanol on the secretion of phospholipase A2 and on its activity was determined. It was found that ethanol inhibited phospholipase A2 secretion but not its activity. By contrast, the activity of the cytosolic form of phospholipase A2 was inhibited by ethanol.