5-Hydroxytryptamine uptake by blood platelets of unipolar and bipolar depressed patients.

The active transport of 5-hydroxytryptamine (5HT) by blood platelets of unipolar and bipolar depressed patients was determined. The 5HT uptake by platelets of bipolar patients was determined in depressive, euthymic and manic states. The 5HT uptake was always followed by studying platelets of healthy individuals of the same sex and age. The results confirm the known fact that there is a decreased 5HT active transport in platelets of unipolar depressed patients. On the other hand, the amount of 5HT transported by platelets of bipolar depressed patients was higher than that observed in platelets of healthy individuals. In manic and euthymic bipolar patients the uptake was similar to their matched controls.