Decreased Dopamine D2 Receptor Bnding in Striatum in Essential Blepharospasm

Abstract

Purpose: : Essential blepharospasm (EB) is classified as a form of focal dystonia, and characterized by involuntary eyelid spasms. Damage in basal ganglia has been suggested to play an important role in genesis of EB, but the exact pathophysiology of EB is currently unclear. The purpose of this study is to investigate the dopamine D₂ receptor binding in the brains of patients with EB.

Methods: : Magnetic resonance imaging (MRI) , and positron emission tomography (PET) were performed in 9 EB patients (2 men, 7 women, mean age = 53.7 years) and 9 age and sex matched controls. Mesurement of the in vivo binding of the dopamine D₂ receptor was performed by [¹¹C]raclopride. Regions of interest (ROIs) were placed on bilateral caudate and putamen, and regional dopamine D₂ receptor bindings were evaluated.

Results: : MRI revealed no particular lesion in the brains of EB patients. A significant decrease in dopamine D₂ receptor bindings were observed in bilateral caudate and putamen of EB patients ( p<0.05). The mean decreases were 13% in caudate and 10% in putamen.

Conclusions: : Decreased dopamine D₂ receptor binding in striatum may be involved in the pathophysiology of EB.

Keywords: eyelid • neuro-ophthalmology: cortical function/rehabilitation • dopamine