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SPECT imaging of striatal dopamine release after amphetamine challenge
M Laruelle1, A Abi-Dargham, C H van Dyck
1Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut.
Summary
This study shows that SPECT imaging can measure dopamine release in the brain after dextroamphetamine sulfate (d-amphetamine) administration. This technique correlates brain changes with emotional responses, aiding in understanding neurochemistry.
Area of Science:
- Neuroimaging
- Radiochemistry
- Pharmacology
Background:
- Dopamine plays a crucial role in regulating mood and behavior.
- Assessing dopamine release in humans non-invasively is challenging.
- Single-photon emission computed tomography (SPECT) offers potential for in vivo neurochemical studies.
Purpose of the Study:
- To evaluate the feasibility of using SPECT with [123I]iodobenzamide ([123I]IBZM) to image intrasynaptic dopamine release.
- To assess the neurochemical correlates of emotional responses induced by dextroamphetamine sulfate (d-amphetamine).
Main Methods:
- Utilized a bolus plus constant infusion of [123I]IBZM for stable SPECT imaging.
- Administered d-amphetamine (0.3 mg/kg IV) to healthy subjects during tracer infusion.
- Measured behavioral effects (euphoria, alertness, restlessness, anxiety) via self-rating scales.
Main Results:
- SPECT imaging revealed a 15% decrease in D2 receptor availability post-d-amphetamine.
- Behavioral responses like euphoria and alertness correlated with reduced D2 receptor availability.
- Anxiety levels showed a weaker correlation with the observed neurochemical changes.
Conclusions:
- Demonstrated the feasibility of using [123I]IBZM SPECT for measuring endogenous dopamine release.
- This method allows for the study of brain neurochemical underpinnings of emotions.
- Highlights the utility of SPECT in challenge testing for neurochemical research.