Striatal Synaptic Dysfunction in Dystonia and Levodopa-Induced Dyskinesia.

This review provides an overview of the synaptic dysfunctions of neuronal circuits and underlying neurochemical alterations observed in the hyperkinetic movement disorders, dystonia and dyskinesia. These disorders exhibit similar changes in expression of synaptic plasticity and neuromodulation. This includes alterations in physical attributes of synapses, synaptic protein expression, and neurotransmitter systems, such as glutamate and gamma-aminobutyric acid (GABA), and neuromodulators, such as dopamine, acetylcholine, serotonin, adenosine, and endocannabinoids. A full understanding of the mechanisms and consequences of disruptions in synaptic function and plasticity will lend insight into the development of these disorders and new ways to combat maladaptive changes.