Interaction of local anaesthetics with blood platelet aggregation.

The effect of three newly synthesized local anaesthetics on platelet aggregation, serotonin release and integrity of platelets was investigated. Pentacaine, heptacaine and carbisocaine were found to be about 10 times more active than "classic" local anaesthetics. They inhibited platelet aggregation stimulated by collagen, thrombin and ADP at the concentrations of 0.01, 0.1 and 1 mmol/l respectively. At millimolar concentrations the test local anaesthetics liberated serotonin from platelets and disintegrated platelet membranes. Pentacaine was the most effective, followed by heptacaine and carbisocaine. The authors suppose that the perturbation induced in platelet membranes by local anaesthetics could be responsible for inhibition of platelet aggregation and release of serotonin.