The vesicular monoamine transporter (VMAT2) plays a major role in the synaptic accumulation and quantal release of monoamines. In this study, we assessed high affinity [3H]dihydrotetrabenazine binding to platelet VMAT2, in a group of untreated male Tourette's syndrome (TS) patients (age: 8-17.5 years, n = 9) and in a group of age- and sex-matched healthy controls (age: 9-16 years, n = 16). Significantly decreased platelet VMAT2 density (Bmax) (- 23%, p = 0.016) was observed in the TS patients. The affinity (Kd) of the ligand to platelet VMAT2 was similar in both groups. If the lower platelet VMAT2 density also occurred in the brain, it may have serve as an adaptive mechanism geared to decrease dopamine storage in the presynaptic neurons and thereby to attenuate the dopaminergic overactivity and ameliorate the movement disorder.
- Attention deficit hyperactivity disorder
- Obsessive-compulsive disorder (OCD)
- Tourette's syndrome
- Vesicular monoamine transporter 2 (VMAT2)