Blood platelets as a peripheral marker for the central serotonin system

Abstract

Platelet 5-HT uptake rate, 3H-imipramine binding and monoamine oxidase activity are reviewed and compared with those of preparations of nerve endings (synaptosomes). The properties of the 5-HT uptake mechanisms in platelet and brain seem to be very similar in most respects and the platelets therefore provide a useful model for brain 5-HT uptake. There is evidence both of genetic, stable control of the uptake and of a state-dependent modifying influence. The findings of some recent studies regarding the platelet 5-HT uptake rates in various psychiatric disorders are reviewed. A consistent finding seems to be a lower Vmax in patients with unipolar depression than in controls. The 3H-imtpramine binding also shows characteristics very similar to that of brain synaptosomes. Although this receptor is functionally linked to 5-HT uptake the density of imipramine binding (Bmax). is obviously independent of 5-HT uptake rates. In the case of imipramine binding the evidence for some form of constitutional (trait-depe...