Localization and physiological roles of metabotropic glutamate receptors in the direct and indirect pathways of the basal ganglia.

Our current understanding of the circuitry of the basal ganglia, and the pathophysiology of Parkinson's disease has led to major breakthroughs in the treatment of this debilitating movement disorder. Unfortunately, there are significant problems with the currently available pharmacological therapies that focus on dopamine replacement or dopaminergic agonists. Because of this, much effort has been focused on developing novel targets for the treatment of Parkinson's disease. The metabotropic glutamate receptors are a family of G-protein coupled receptors activated by glutamate. These receptors are differentially distributed throughout the basal ganglia in a manner suggesting that they may provide novel targets for the treatment of movement disorders. In this review we summarize anatomical and physiological data from our work and the work of other laboratories describing the distribution and physiological roles of metabotropic glutamate receptors in the basal ganglia with emphasis on possible therapeutic targets.