ADRENALINE-INDUCED PLATELET-AGGREGATION IN DEPRESSED-PATIENTS AND CONTROL SUBJECTS

We measured alpha2-adrenoceptor-mediated platelet primary aggregation in depressed patients and healthy subjects. Both initial velocity and maximum amplitudes of platelet response to increasing concentrations o f adrenaline were decreased in drug-free depressed patients as compare d with controls. The EC50 of both initial slope and maximum amplitude were also increased in drug-free depressed patients. The results sugge sted a lowered platelet alpha2-adrenoceptor function. Demographic fact ors (age and sex) and the time between blood collection and start of a ggregation monitoring did not influence the results. This report is co nsistent with postsynaptic receptor desensitization in depressed patie nts. The precise molecular mechanism for this impairment remains to be elucidated.