Grant: Operating Grant

Parkinson's disease affects 1 of approximately 272 Canadians. The most widely used form of drug treatment for Parkinson's disease targets dopamine receptors in the brain. Unfortunately, some patients receiving drug treatment experience psychiatric and motor complications such as dyskinesias and impulse control disorder. Scientists are currently interested in the possibility that the D3 dopamine receptor is contributing to these complications We recently showed that D3 receptor levels (but not D2) are low in never-treated patients with Parkinson's and above normal in patients who have received treatment and developed impulse control disorder (expressed as pathological gambling). At present, very little is known about the D3 receptor subtype in stable patients receiving treatment for Parkinson's. We propose to use positron emission tomography (PET brain imaging) to image the level of D2 and D3 receptors in the brains of patients with Parkinson's. We will investigate dopamine receptor levels in patients who have never received treatment, in stable treated patients and in healthy matched-controls. We hypothesize that patients receiving dopamine replacement therapy will have greater D3 binding and lower D2 binding compared to patients who have never received treatment. This study will contribute to our understanding of the involvement of D3 receptors in Parkinson's and will provide insight into developing drugs to fight this disease.