Striatal dopamine transporter density in major depression.
BACKGROUND
There are no previous data available regarding [123I]beta-CIT binding to the dopamine transporter sites in the basal ganglia in depressed patients.


OBJECTIVE
The present study tested the hypothesis that the brain DAT density in depressed patients is lower than that in matched healthy controls.


METHODS
Fifteen drug-naive outpatients with major depression and 18 healthy controls were investigated using single photon emission computerized tomography (SPECT) with a high-affinity dopamine transporter specific radioligand. 123I-labeled beta-CIT (2beta-carbomethoxy-3beta-(4-iodophenyl-tropane).


RESULTS
We found a significantly higher [123I]beta-CIT uptake in both sides of the basal ganglia in patients with major depression than in the controls (Mann-Whitney U-test, P = 0.002 on the right and P = 0.003 on the left).


CONCLUSIONS
The radioligand uptake reflecting the DAT density was significantly higher among the patients than in the controls. This finding is unexpected, since it is generally believed that monoaminergic neurotransmission is lower in depression, and therefore it could be assumed that a reduction in dopamine transmission would lead to secondary down-regulation of DAT density. However, it is possible that up-regulation of the DAT may be the primary alteration, which leads to lower intrasynaptic dopamine concentration and to lower dopamine neural transmission.
Laasonen-Balk
T
T
Department of Psychiatry, Kuopio University Hospital, Finland.
Kuikka
J
J
Viinamäki
H
H
Husso-Saastamoinen
M
M
Lehtonen
J
J
Tiihonen
J
J
D000704:Analysis of Variance; D002352:Carrier Proteins / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D003865:Major Depressive Disorder / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D006801:Humans; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D015899:Tomography, Emission-Computed, Single-Photon
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493214:SLC6A3 protein, human