Kinetic values of active serotonin transport by platelets of bipolar, unipolar and schizophrenic patients at 2 and at 8 a.m. Preliminary report.

Serotonin active transport by platelets of psychiatric patients was determined at 2 and at 8 a.m. Kinetic values, Vmax and Km, of serotonin uptake by platelets of bipolar depressive patients at 2 a.m. were higher than those at 8 a.m. Contrary to that, the kinetic values, Vmax and Km, for unipolar patients at 2 a.m. were rather lower than the values at 8 a.m. Serotonin uptake kinetics by platelets of schizophrenic patients at 2 a.m. were similar to those at 8 a.m. The curves of serotonin uptake kinetics by platelets of bipolar patients at 2 and at 8 a.m. were different from those observed for platelets of unipolar and schizophrenic patients. The variability of the kinetics of serotonin uptake by platelets of the three groups of psychiatric patients may offer a clue to the heterogenicity of these disorders.