raclopride and Blepharospasm

The purpose of this study was to investigate whether dopamine D(2) receptor binding was altered in the striatum of essential blepharospasm patients.. Striatal dopamine D(2) receptor binding was measured with positron emission tomography and [(11)C]raclopride. We studied eight drug-naive patients with bilateral blepharospasm and eight age-matched normal controls.. The uptake indices in the blepharospasm group were significantly reduced by 11.7% in the caudate (P < 0.005), 11.6% in the anterior putamen (P < 0.0001), and 10.3% in the posterior putamen (P < 0.005) relative to the control group.. This study indicates decreased dopamine D(2) receptor binding in the entire striatal region of blepharospasm patients. The findings suggest that decreased dopamine D(2) receptor binding might be one of the predisposing factors that leads to the dysfunction of the motor circuit, resulting in the loss of broad inhibition of unwanted movements during an intended movement in blepharospasm patients.

Topics: Blepharospasm; Botulinum Toxins; Carbon Radioisotopes; Corpus Striatum; Dopamine Antagonists; Female; Humans; Male; Middle Aged; Positron-Emission Tomography; Raclopride; Radiography; Receptors, Dopamine D2; Reference Values

Functional neuroimaging, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), provides a valuable technique for detecting regional changes in brain metabolic activity associated with human disease. These techniques have been applied in different dystonic disorders including primary generalized dystonia and dopa-responsive dystonia (DRD), as well as focal dystonic syndromes such as torticollis, writer's cramp, and blepharospasm. A common finding is abnormality of the basal ganglia and associated outflow pathways to sensorimotor cortex and other regions involved with motor performance. Other recent imaging research has utilized diffusion-based MRI techniques to localize distinct microstructural abnormalities in dystonia patients and gene carriers. This presentation will focus on an integrated approach to understanding the pathophysiology of this genetic and biochemically diverse disorder.

Topics: Anisotropy; Basal Ganglia; Blepharospasm; Carbon Radioisotopes; Case-Control Studies; Dihydroxyphenylalanine; Dopamine Antagonists; Dystonia; Dystonic Disorders; Globus Pallidus; Heterozygote; Humans; Magnetic Resonance Imaging; Molecular Chaperones; Motor Cortex; Positron-Emission Tomography; Prospective Studies; Putamen; Raclopride; Receptors, Dopamine; Torticollis