Influence of epinephrine on the aggregation response of aspirin-treated platelets.

We have evaluated the influence of epinephrine on the sensitivity of aspirin-treated platelets to aggregating agents. Concentrations of ADP, thrombin and arachidonate that caused reversible stimulation of aspirin platelets produced irreversible aggregation when the aspirin samples had been pretreated with epinephrine. The correction was not due to improvement in the ability of aspirin platelets to synthesize prostaglandins or secrete products of the release reaction. Epinephrine induced correction of refractory aspirin platelets may help to explain why aspirin is not a universally effective anti-thrombotic agent.