Increased density of the platelet serotonin transporter in autism

Background: Various data have shown the involvement of serotonin (5-HT) in autism. The presence of the 5-HT transporter in platelets, similar to the s ame structure located in presynaptic serotonergic neurons, has produced a s eries of studies aimed at assessing its functionality in this disorder, but the ensuing findings are quite controversial. For this reason, we investig ated the 5-HT transporter by means of the specific binding of [H-3]-Paroxet ine ([H-3]-Par), which is currently considered the first-choice ligand for labeling it, in platelets of 20 autistic children and adolescents, as compa red with healthy control subjects, Methods: Twenty children and adolescents of both sexes suffering from autism according to DSM IV criteria were incl uded in the study and compared with a similar group of healthy control subj ects. Platelet membranes and the binding of [H-3]-Par were carried out acco rding to standardized protocols. Results: The results showed a significantl y higher density of [H-3]-Par binding sites in autistic children than in he althy control subjects. Conclusions: These findings support the presence of a serotonergic dysfunction in autism and would suggest that the 5-HT trans porter may have a specific role in this disorder, also in the light of its recently proposed role in brain development.