Effect of mental stress on platelet aggregation: possible link to catecholamine levels

The present study was aimed at testing the hypothesis about the relation between mental stress and platelet function. Plasma samples were obtained from 100 students immediately before, and 30 min and 7 h after undergoing a bleeding time test, which was used as mental stressor. Platelet responses to serotonin, ADP and collagen, as well as plasma catecholamine levels were assayed. Plasma serotonin levels had a high negative correlation with the bleeding time. Stress resulted in an increase in platelet responses to serotonin, ADP and to the elevation of catecholamine levels. Furthermore, a significant negative correlation between the platelet aggregation induced by ADP and collagen and the bleeding time was demonstrated. It is concluded that mental stress had a significant effect on platelet aggregation. This study provides evidence of increased platelet aggregability in association with elevated plasma catecholamine levels.