Effects of ethanol on platelet aggregation: an in vitro study.

Alcohol ingestion results in the formation of circulating microaggregates in the pig. To investigate the underlying mechanism, the effects of alcohol on platelet aggregation using a Born-aggregometer, was investigated. After incubating unstirred platelet rich plasma (PRP) with moderate concentrations of alcohol (175 mmol/l) the aggregation induced by collagen was reduced. This was probably due to platelet refractoriness caused by platelet ADP release. We could also demonstrate that high concentrations of alcohol (630 mmol/l) caused platelet release in stirred PRP. Release of ADP from red cells, after incubating unstirred whole blood with low concentrations of alcohol (17 mmol/l), was the probable explanation to the observed platelet refractoriness to ADP and collagen. Alcohol causing release of ADP from red cells is likely the cause of platelet aggregation in circulating blood and is probably the mechanism in formation of circulating platelet aggregates after alcohol ingestion.