Dopamine D(2) receptor availability and amphetamine-induced dopamine release in unipolar depression.
BACKGROUND
Reduced dopaminergic transmission has been implicated in the pathophysiology of major depression. The aim of the present study was to measure striatal D(2) receptor availability and amphetamine-induced dopamine release in nonpsychotic, unmedicated, unipolar patients during an episode of major depression.


METHODS
The striatal equilibrium specific to nonspecific partition coefficient (V(3)") of the D(2) receptor antagonist [(123)I]IBZM was measured with single photon emission computerized tomography before and after amphetamine administration in 9 depressed subjects and 10 matched healthy control subjects.


RESULTS
No significant differences were observed in preamphetamine D(2) receptor availability between depressed patients (0.73 +/- 0.08) and control subjects (0.78 +/- 0.10, p =.23). Amphetamine-induced reduction in [(123)I]IBZM V(3)" (DeltaV(3)") was similar in depressed patients (-9.8 +/- 5.5%) and control subjects (-7.8 +/- 2.5%, p =.32). Amphetamine induced a transient improvement in symptomatology in depressed patients, but this improvement did not correlate with [(123)I]IBZM DeltaV(3)".


CONCLUSIONS
This study did not replicate previously reported alterations in striatal D(2) receptor density in depressed patients and suggests that stimulant-induced dopamine release is not altered in major depression.
Parsey
R V
RV
Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA.
Oquendo
M A
MA
Zea-Ponce
Y
Y
Rodenhiser
J
J
Kegeles
L S
LS
Pratap
M
M
Cooper
T B
TB
Van Heertum
R
R
Mann
J J
JJ
Laruelle
M
M
D000293:Adolescent; D000328:Adult; D000661:Amphetamine / Q000493:pharmacokinetics / Q000494:pharmacology*; D001549:Benzamides; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D015899:Tomography, Emission-Computed, Single-Photon
D001549:Benzamides; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide; D000661:Amphetamine; D004298:Dopamine