DECREASED PLATELET H-3 PAROXETINE BINDING IN OBSESSIVE-COMPULSIVE PATIENTS

The similarities between the serotonin (5-HT) transporter in both huma n platelets and human brain permit us to investigate this structure in patients with different psychiatric disorders. Several reports have s hown abnormalities of the 5-HT transporter, by means of the measuremen t of the 5-HT uptake or of the H-3-imipramine binding, in platelets of patients with obsessive-compulsive disorder (OCD). The availability o f the ligand H-3-paroxetine, a selective 5-HT reuptake inhibitor, to l abel the 5-HT transporter, promoted us to evaluate the binding of H-3- paroxetine in platelets of 18 drug-free patients with OCD. The results , showing that the patients had a lower number of H-3-paroxetine sites , wich is inversely correlated with the Yale Brown Obsessive-Compulsiv e Scale total score, than a similar group of controls, add supporting evidence to the involvement of 5-HT in OCD. In addition, the decreased functionality of the 5-HT transporter seems to be linked to the sever ity of OC symptoms.