Decreased lymphocyte 3H-paroxetine binding in obsessive-compulsive disorder.

The pathophysiology of obsessive-compulsive disorder (OCD) is mainly focused on the serotonin (5-HT) system and transporter. The presence of this structure in blood lymphocytes prompted us to investigate it, by means of the specific binding of (3)H-paroxetine ((3)H-PAR), in a group of drug-free OCD patients as compared with healthy control subjects matched for sex and age. Lymphocyte membranes and (3)H-PAR binding were carried out according to standard protocols. The results showed that the patients had a statistically significant lower density of (3)H-PAR-binding sites than the control subjects. On one hand, this finding confirms previous data of an abnormal platelet 5-HT transporter in OCD, on the other it provides the possibility to explore the regulation of this structure in this and other disorders, since lymphocytes are nucleate cells.