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 same structure located in presynaptic serotonergic neurons, has produced a series of studies aimed at assessing its functionality in this disorder, but the ensuing findings are quite controversial. For this reason, we investigated the 5-HT transporter by means of the specific binding of [3H]-Paroxetine ([3H]-Par), which is currently considered the first-choice ligand for labeling it, in platelets of 20 autistic children and adolescents, as compared with healthy control subjects.

METHODS

Twenty children and adolescents of both sexes suffering from autism according to DSM IV criteria were included in the study and compared with a similar group of healthy control subjects. Platelet membranes and the binding of [3H]-Par were carried out according to standardized protocols.

RESULTS

The results showed a significantly higher density of [3H]-Par binding sites in autistic children than in healthy control subjects.

CONCLUSIONS

These findings support the presence of a serotonergic dysfunction in autism and would suggest that the 5-HT transporter may have a specific role in this disorder, also in the light of its recently proposed role in brain development.