Sensitivity of thrombin-induced platelet aggregation to inhibition by ethanol

Background: The purpose of this study was to determine the concentration of ethanol required for inhibition of thrombin-induced aggregation of human platelets in vitro. Methods: Three methods, light transmission method, particle counting method using light scattering and screen filtration pressure method using whole blood, were used for evaluation of platelet aggregation. Results: Thrombin (0.2 U/ml)-induced platelet aggregation was significantly inhibited by ethanol, and the threshold ethanol concentrations for inhibition determined by measurements using the light transmission method, particle counting method and screen filtration pressure method were 0.5%, 0.125% and 2%, respectively. Platelet aggregation induced by a lower concentration (0.05 U/ml) of thrombin was detected by the screen filtration pressure method but not by the light transmission method or particle counting method. The threshold ethanol concentration for the inhibition of thrombin (0.05 U/ml)-induced platelet aggregation was 0.125% according to results obtained by using the screen filtration pressure method. Conclusions: Sensitivities for detection of thrombin-induced platelet aggregation and for detection of inhibition of platelet aggregation by ethanol were high in the screen filtration pressure method and the particle counting method, respectively. The threshold concentration of ethanol to inhibit thrombin-induced platelet aggregation is about 0.125% (approximately 21 mmol/l), which is easily attainable after drinking alcohol. (c) 2009 Elsevier B.V. All rights reserved.