Vesicular monoamine transporter concentrations in bipolar disorder type I, schizophrenia, and healthy subjects.
BACKGROUND
Previous analyses of vesicular monoamine transporter (VMAT2) binding in euthymic bipolar disorder type I (BDI) patients have shown increases of this presynaptic marker in the thalamus and ventral midbrain. To assess the diagnostic specificity of those findings, we compared VMAT2 concentrations between euthymic BDI patients, patients diagnosed with schizophrenia (SCH), and age-matched healthy volunteers.


METHODS
Binding sites for VMAT2 were quantified with (+)-alpha-[11C]DTBZ (dihydrotetrabenazine) and positron emission tomography. Fifteen euthymic BDI and 12 SCH patients and 15 group-matched healthy controls were studied. [11C]DTBZ tracer transport and binding potentials were examined in the thalamus and ventral midbrain with factorial analyses of variance and post hoc Tukey's honestly significantly different tests.


RESULTS
Analysis of variance detected diagnosis effects in binding potentials in both brain regions. Binding of VMAT2 in the thalamus was higher in BDI patients than in control subjects and SCH patients. Conversely, ventral brainstem binding was nearly identical between BDI and SCH patients and were higher than in the control group.


CONCLUSIONS
The patterns of regional VMAT2 expression, and by extension, the concentration of monoaminergic synaptic terminals, differ between BDI, SCH, and a control group. These findings may relate to both similarities and differences in the presentation or clinical course of these syndromes and require further examination.
Zubieta
J K
JK
The University of Michigan, Mental Health Research Institute, Neuroscience Building, 1103 E. Huron St., Ann Arbor, MI 48104-1687, USA.
Taylor
S F
SF
Huguelet
P
P
Koeppe
R A
RA
Kilbourn
M R
MR
Frey
K A
KA
D000328:Adult; D001714:Bipolar Disorder / Q000378:metabolism* / Q000523:psychology; D001923:Brain Chemistry / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009479:Neuropeptides; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000378:metabolism*; D012565:Schizophrenic Psychology; D014055:Tomography, Emission-Computed; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009479:Neuropeptides; C493452:SLC18A2 protein, human; D050492:Vesicular Biogenic Amine Transport Proteins; D050493:Vesicular Monoamine Transport Proteins