A Comprehensive Assessment of Dopaminergic Function in Tourette Syndrome Using Novel Positron Emission Tomography Ligands

Grant Type
Grant Year
Institution Location
Institution Organization Name
University of Toronto Canada
Investigators Name
Strafella, Antonio, MD, PhD

Tourette Syndrome (TS) is a disorder that presents in childhood with chronic vocal and motor tics, often in association with behavioral disturbances such as Obsessive-Compulsive Disorder (OCD) and Attention Deficit Hyperactivity Disorder (ADHD). Evidence from both pharmacological trials and selected imaging studies suggests that abnormalities of the dopaminergic neurotransmitter system play a key role in TS development. Indeed, one hypothesis is that the disorder is associated with excessive activity of dopamine in the brain. Despite the substantial evidence implicating dopaminergic dysfunction in the disorder, specific attempts to determine the nature of the abnormality using conventional functional imaging techniques have generated contradictory findings. Neurotransmitters (brain chemicals) can be studied using a technique called Positron Emission Tomography (PET). This is done by injecting a small amount of a radioactively labelled substance (ligand) into the blood stream and then imaging the ligand as it binds to the receptors in the brain that would normally bind to a given neurotransmitter. The development of new PET ligands ([11C]- FLB 457 and [11C]-(+)- PHNO ) that bind specifically to dopamine receptors enables us to more accurately assess dopaminergic function in the human brain than was previously possible. As these ligands have not yet been applied to an analysis of TS, we propose using them in a comprehensive re-evaluation of neurotransmitter function in adults with TS. We anticipate that the study will provide information that may enable us to either support or refute the dopamine hypothesis of TS, and thereby provide new insights into the mechanism of the disorder. Study results may also guide the community in the selection and development of rational pharmacological therapies, and perhaps enable us to more accurately target specific interventions. Antonio P. Strafella, M.D., Ph.D., Anthony Lang, M.D., Paul Sandor, M.D., Thomas Steeves, M.D. University of Toronto Toronto, Canada Award: $73,920 Tourette Association of America Inc. – Research Grant Award 2007-2008