PERIPHERAL MARKERS OF SEROTONIN AND DOPAMINE FUNCTION IN OBSESSIVE-COMPULSIVE DISORDER

In an attempt to clarify the possible role of a serotonergic and dopaminergic dysfunction in obsessive-compulsive disorder (OCD), we measured platelet H-3-imipramine (H-3-IMI) binding, serotonin uptake, and platelet sulfotransferase activity in 17 drug-free OCD patients and an equal number of healthy controls. Serotonin uptake and H-3-IMI binding sites in platelets have been shown to constitute peripheral markers of those present in presynaptic serotonergic neurons. Sulfotransferase, an enzyme involved in the catabolism of phenolic compounds and of cathecholamines such as dopamine, has similar kinetic characteristics in brain and platelets. Our results showed a lower number of H-3-IMI binding sites and a higher level of sulfotransferase activity in OCD patients compared with those in controls. These preliminary results suggest involvement of both the serotonin and dopamine systems in OCD.