title: Elevated platelet vesicular monoamine transporter density in untreated patients diagnosed with major depression.
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 (B(max)) was observed in the platelets of untreated MDD patients (+24%) compared to healthy control subjects. No significant change was found in the affinity constant (K(d)). 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.
authors.affiliation: Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Zucker
authors.forename: Alex
authors.initials: A
authors.lastname: Aviv
authors.forename: Assaf
authors.initials: A
authors.lastname: Shelef
authors.forename: Abraham
authors.initials: A
authors.lastname: Weizman
authors.forename: Moshe
authors.initials: M
authors.lastname: Rehavi
mesh_terms: D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D003865:Major Depressive Disorder / Q000097:blood* / Q000175:diagnosis / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood*; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009479:Neuropeptides; D011869:Radioligand Assay; D012008:Recurrence; D013747:Tetrabenazine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
chemical_list: D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009479:Neuropeptides; C493452:SLC18A2 protein, human; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; C032811:dihydrotetrabenazine; D013747:Tetrabenazine