Summary
Ethanol at physiologically tolerable concentrations inhibited platelet aggregation
in vitro in a relatively specific way, which may be influenced by platelet membrane
lipid composition. Aggregation to collagen, calcium ionophore A23187 and thrombin
(low doses) were often markedly inhibited by ethanol, adrenaline and ADP responses
were little affected, and aggregation to exogenous arachidonic acid was actually potentiated
by ethanol. Aggregation to collagen, thrombin and A23187 was inhibited more by ethanol
in platelets enriched with saturated fatty acids than in those enriched with unsaturated
fats. Platelets enriched with cholesterol showed increased sensitivity to ADP, arachidonate
and adrenaline but this increase in cholesterol content did not appear to influence
the inhibition by ethanol of platelet responses. The results suggest that ethanol
may inhibit aggregation by an effect on membrane fluidity and/or calcium mobilization
resulting in decreased activity of a membrane-bound phospholipase.
Keywords
Platelet inhibition - Ethanol - Membrane phospholipids
