Moving toward a new treatment for Parkinson's disease
Scientists who study Parkinson's disease know well that the loss of dopamine-producing cells in the brain is a key trait of this disorder and leads to impaired physical movement.
They have long suspected that dopamine itself may contribute to the death of these neurons.
Gary Miller, Asa Griggs Candler Professor of Environmental Health and associate dean for research at Rollins, previously demonstrated that all-important dopamine becomes a liability when improperly stored inside brain cells. Now his research team has turned that liability into an asset. In a recent study, Miller's laboratory found that it is possible to enhance the storage of dopamine, which could lead to improved treatments for Parkinson's.
Dopamine and other neurotransmitters are stored in small packages called vesicles, which are controlled by a protein called vesicular monoamine transporter, or VMAT2. When dopamine is released from these vesicles, it helps regulate physical movement and emotional responses.
Using mice genetically engineered with an extra VMAT2 protein, Miller's team showed that more dopamine is released, leading to a remarkable increase in movement and a decrease in anxiety and depressive behaviors. Not only did the mice store more dopamine in their brains, they also released more of it when needed. They also were resistant to a classical toxin used to study Parkinson's.
Miller's team is now focusing on identifying drugs that could exploit these findings to help treat the estimated 8 to 10 million people globally who have Parkinson's disease.
"Our work suggested that enhanced dopamine storage can be sustained over time and may be a viable therapeutic approach for a variety of central nervous system disorders that involve the storage and release of dopamine, serotonin, or norepinephrine," says Miller. "Parkinson's disease is the obvious place to start."
Results from Miller's study were published in the July 8, 2014, edition of Proceedings of the National Academy of Sciences (PNAS). Learn more about his study at bit.ly/PNAS-dopamine.
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