Abstract
The intraneuronal uptake of monoamines into brain synaptic vesicles is mediated by the vesicular monoamine transporter (VMAT2). This transporter plays a major role in monoamine storage and quantal release. Recently we demonstrated a high degree of similarity between the pharmacodynamic characteristics of platelet and brain VMAT2. In the present study we measured the VMAT2 density, using [3H]dihydrotetrabenazine ([3H]TBZOH) as a ligand, in platelets of untreated patients diagnosed with major depressive disorder (MDD) (n=10; three with recurrent depression and seven with first episode depression) compared to sex- and age-matched healthy control subjects (n=23). A significant elevation in the VMAT2 density (Bmax) was observed in the platelets of untreated MDD patients (+24%) compared to healthy control subjects. No significant change was found in the affinity constant (Kd). The increased platelet VMAT2 density may reflect depression-related enhancement of the capacity to accumulate monoamines in the vesicles in the presence of lower monoamine turnover.
Original language | English |
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Pages (from-to) | 251-256 |
Number of pages | 6 |
Journal | Psychiatry Research |
Volume | 112 |
Issue number | 3 |
DOIs | |
State | Published - 15 Nov 2002 |
Keywords
- Depression
- Platelet
- Vesicular monoamine transporter
- [H]dihydrotetrabenazine