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Dopamine D(2) receptor availability and amphetamine-induced dopamine release in unipolar depression
R V Parsey1, M A Oquendo, Y Zea-Ponce
1Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA.
Biological Psychiatry
|September 7, 2001
Summary
Major depression may not involve altered striatal D2 receptor availability or dopamine release. This study found no significant differences in dopamine D2 receptors or amphetamine-induced dopamine release in depressed patients compared to controls.
Area of Science:
- Neuroscience
- Psychiatry
- Radiology
Background:
- Dopaminergic transmission dysfunction is a suspected factor in major depression.
- Previous research suggested altered striatal D2 receptor availability in depression.
Purpose of the Study:
- To measure striatal D2 receptor availability in unmedicated, unipolar depressed patients.
- To assess amphetamine-induced dopamine release in these patients using SPECT imaging.
Main Methods:
- Single photon emission computerized tomography (SPECT) was used to measure the striatal equilibrium specific to nonspecific partition coefficient (V(3)") of the D2 receptor antagonist [(123)I]IBZM.
- Measurements were taken before and after amphetamine administration in 9 depressed patients and 10 healthy controls.
Main Results:
- No significant differences in baseline D2 receptor availability were found between depressed patients and controls.
- Amphetamine-induced dopamine release, measured as the reduction in [(123)I]IBZM V(3)" (DeltaV(3)"), was similar in both groups.
- While amphetamine transiently improved depression symptoms, this effect did not correlate with dopamine release.
Conclusions:
- This study did not find evidence of altered striatal D2 receptor density in major depression.
- The findings suggest that stimulant-induced dopamine release is not significantly different in major depression.