Dopamine is a chemical messenger in the brain associated with happiness. It affects reward-based behaviors and motivation, as well as movement. Treatments for Parkinson’s disease have been mostly focused on this chemical. Researchers from Yale University, through their new study, challenge the long-held assumptions about the sole role of dopamine in this degenerative disorder.
In people with Parkinson’s disease, nerve cells that produce dopamine slowly die. The loss of dopamine leads to slower movements, resting tremors, and other symptoms that worsen over time. To reverse parkinsonism — the collection of symptoms seen in Parkinson’s disease — doctors provide a treatment that increases dopamine levels in the striatum, a portion of the brain that is responsible for motor learning. However, medical treatments do not consider the effects of parkinsonism on another neurotransmitter, acetylcholine.
Scientists had previously believed that when dopamine levels dropped, acetylcholine levels increased. However, this relationship had never been thoroughly investigated, despite acetylcholine’s likely role in creating a movement disorder called dyskinesia, which develops in most patients after several years of dopamine treatment for parkinsonism.
Neurology professor Nigel S. Bamford, together with his fellow researchers, explored the relationship between dopamine and acetylcholine through the use of mice. This is what they found out.
...Bamford and his co-authors learned, motor function in parkinsonism becomes dependent on both dopamine and acetylcholine.
These findings suggest that treating parkinsonism may require targeted therapies that restore the balance between these two chemicals, instead of focusing solely on dopamine, said the researchers.
See the full study here.
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