Dopamine and dyskinesia: investigating new areas of the brain
Eric Dumont, Associate Professor, Faculty of Health and Sciences, Queen's University
Scientific Title: Neurophysiological trace of L-DOPA-induced dyskinesia in the bed nucleus of the tria terminalis of 6-OHDA-lesioned rats
For people with Parkinson's disease, involuntary movements known as dyskinesias are one of the frustrating side-effects of the long-time use of dopamine replacement medication to reduce the tremors, stiffness and rigidity the disease induces.
Most of the research into how to reduce dyskinesia has concentrated on the basal ganglia, the part of the brain directly related to motor function. At Queen's University, neuroscientist Eric Dumont is investigating another part of the brain, which modulates fear and anxiety.
The bed nucleus of the stria terminalis, or BNST, contains clusters of brain cells and is part of the amygdala, the area of the brain that processes memory and emotion. Dumont believes the BNST is also affected by the dopamine that drugs like levodopa provide to try to replace the dopamine that is being depleted in Parkinson's.
If the BNST gets flooded with too much dopamine, which is a signalling chemical, that could result in the dyskinesias, says Dumont.
“One of the problems is that we cannot give dopamine in the same ways as the brain would naturally provide it,” Dumont says.
Working in close collaboration with a colleague in France, Dumont is using an animal model to observe the effects of interfering with or blocking the excess dopamine in the BNST, to see if reducing the dopamine in that area of the brain also reduces dyskinesia.
Because the BNST is also involved in anxiety and fear, any type of drug therapy that blocks the excess dopamine there could also have a positive effect on some of the non-motor symptoms of Parkinson's disease, like anxiety and depression.
“This is definitely another avenue that we will investigate,” Dumont says.
Dumont, who has spent much of his earlier research studying the areas of the brain involved in addiction, is excited by the energy Parkinson's researchers are generating.
“We're pretty optimistic about where we could go and how we can contribute here,” he says.