Impulse control disorders in Parkinson's disease: decreased striatal dopamine transporter levels.

Abstract

OBJECTIVE:

Impulse control disorders are commonly associated with dopaminergic therapy in Parkinson's disease (PD). PD patients with impulse control disorders demonstrate enhanced dopamine release to conditioned cues and a gambling task on [(11)C]raclopride positron emission tomography (PET) imaging and enhanced ventral striatal activity to reward on functional MRI. We compared PD patients with impulse control disorders and age-matched and gender-matched controls without impulse control disorders using [(123)I]FP-CIT (2β-carbomethoxy-3β-(4-iodophenyl)tropane) single photon emission computed tomography (SPECT), to assess striatal dopamine transporter (DAT) density.

METHODS:

The [(123)I]FP-CIT binding data in the striatum were compared between 15 PD patients with and 15 without impulse control disorders using independent t tests.

RESULTS:

Those with impulse control disorders showed significantly lower DAT binding in the right striatum with a trend in the left (right: F(1,24)=5.93, p=0.02; left: F(1,24)=3.75, p=0.07) compared to controls.

CONCLUSIONS:

Our findings suggest that greater dopaminergic striatal activity in PD patients with impulse control disorders may be partly related to decreased uptake and clearance of dopamine from the synaptic cleft. Whether these findings are related to state or trait effects is not known. These findings dovetail with reports of lower DAT levels secondary to the effects of methamphetamine and alcohol. Although any regulation of DAT by antiparkinsonian medication appears to be modest, PD patients with impulse control disorders may be differentially sensitive to regulatory mechanisms of DAT expression by dopaminergic medications.

• Authors: Valerie Voon, Alexandra Rizos, Riddhika Chakravartty, Nicola Mulholland, Stephanie Robinson, Nicholas A Howell, Neil Harrison, Gill Vivian, K Ray Chaudhuri
• Journal: Journal of neurology, neurosurgery, and psychiatry (J Neurol Neurosurg Psychiatry) Vol. 85 Issue 2 Pg. 148-52 (Feb 2014) ISSN: 1468-330X [Electronic] England
• PMID: 23899625 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Dopamine Plasma Membrane Transport Proteins
• Iodine Radioisotopes
• Tropanes
• 2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane

Topics

• Case-Control Studies
• Corpus Striatum (diagnostic imaging, metabolism)
• Disruptive, Impulse Control, and Conduct Disorders (complications, diagnostic imaging, metabolism, psychology)
• Dopamine Plasma Membrane Transport Proteins (metabolism)
• Female
• Humans
• Iodine Radioisotopes
• Male
• Middle Aged
• Parkinson Disease (complications, diagnostic imaging, metabolism, psychology)
• Radionuclide Imaging
• Tropanes