title: Decreased platelet vesicular monoamine transporter density in children and adolescents with attention deficit/hyperactivity disorder.
abstract: The aim of the present study was to assess vesicular monoamine transporter (VMAT2) density in attention deficit/hyperactivity disorder (ADHD), a disorder involving monoaminergic dysregulation. It was hypothesized that the hypoactivity of monoaminergic neurotransmission related to ADHD could be associated with an under-expression of VMAT2. We assessed high affinity [3H]dihydrotetrabenazine [TBZOH] binding to platelet VMAT2 in untreated male ADHD children and adolescents (n=11) as compared to age-matched controls (n=14), as well as the correlation between VMAT2 density and the severity of ADHD symptoms as measured by the clinician-administered DSM-IV ADHD Scale (DAS) and the parent-administered Abbreviated Conners' Rating Scale (ACPRS). The [3H]TBZOH binding capacity (Bmax) was significantly lower (17%) in the ADHD group as compared to the controls. There was no difference between the two groups in the affinity (Kd value) of [3H]TBZOH to its binding site. An inverse correlation was found between the ADHD symptom scales and the Bmax values. It remains unclear whether the under-expression of platelet VMAT2 in ADHD children is reflective of a parallel change in the brain, and whether it is primary or an epiphenomenon of ADHD.
authors.affiliation: Tel-Aviv Community Mental Health Center and the Sackler Faculty of Medicine, Tel-Aviv University, Israel.
authors.forename: Paz
authors.initials: P
authors.lastname: Toren
authors.forename: Moshe
authors.initials: M
authors.lastname: Rehavi
authors.forename: Anat
authors.initials: A
authors.lastname: Luski
authors.forename: Netta
authors.initials: N
authors.lastname: Roz
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Laor
authors.forename: Michal
authors.initials: M
authors.lastname: Lask
authors.forename: Abraham
authors.initials: A
authors.lastname: Weizman
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood* / Q000503:physiopathology; D001792:Blood Platelets / Q000378:metabolism*; D002648:Child; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood*; D026901:Membrane Transport Proteins / Q000097:blood*; D011485:Protein Binding / Q000502:physiology; D012720:Severity of Illness Index; D013747:Tetrabenazine / Q000031:analogs & derivatives* / Q000378:metabolism; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
chemical_list: D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; C493452:SLC18A2 protein, human; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; C032811:dihydrotetrabenazine; D013747:Tetrabenazine