Decreased platelet H-3-paroxetine binding in untreated panic disorder patients

Different findings support the involvement of the serotonin (5-HT) system in panic disorder. The presence of the 5-HT transporter in blood platelets similar to that in presynaptic serotonergic neurons, permits the investigation of this structure in periphery., We therefore evaluated the binding of H-3-paroxetine, a selective 5-HT reuptake inhibitor which is considered the ligand of choice for labelling the 5-HT transporter, in platelets of 20 drug-flee patients with panic disorder. The same measurement was repeated after one year's treatment with different drugs. The results showed patients to have-a lower number of H-3-paroxetine sites than a group of age- and sex-matched controls, thus suggesting the involvement of the 5-HT transporter in panic disorder. This abnormality reverted after one year of treatment with specific drugs that provoked the symptom remission in all cases, which would suggest a link with the clinical improvement.