A new report sheds light on how a Parkinson’s disease drug may impair decision-making and lead to harmful behaviors like binge eating, gambling and compulsive shopping.
The study was published last month in the International Journal of Molecular Sciences, and related details were published in a press release Tuesday.
In the study, researchers explored the mechanism by which pramipexole (PPX) interferes in a person’s decision-making process. The investigation was done in mice with Parkinson’s disease, not in humans, but gives a possible foundation for future research. The team was led by Hisayoshi Kubota, an assistant professor from the Fujita Health University in Japan.
Parkinson’s disease is due to a loss of nerve cells or neurons that produce a compound called dopamine. Some neurons count on dopamine to function and have dopamine receptors that can be activated with dopamine. But people with the disease lack the dopamine, so the PPX mimics how dopamine works, so to say, by binding to the receptors.
The team injected a toxin called 6-hydroxydopamine (or 6-OHDA) into the brains of mice. The toxin damages neurons similarly to how the disease does. Next, the mice were treated with PPX and then the scientists gauged their decision-making skills using a touchscreen-based gambling task test. The mice picked the high-risk/high-reward option more often, which was a strawberry milkshake that came with exposure to flashing lights.
An area of the brain called the external globus pallidus (GPe) was hyperactivated, showing a high level of neuron activity. The researchers then chemically inhibited the neurons in the GPe, which actually reduced disadvantageous risk-taking activity in the mice. This proved that hyperactivation of the GPe was responsible for poor decision-making in the mice treated with PPX.
“Our findings could lead to the development of new medications or interventions that specifically target the external globus pallidus,” Kubota said. “This would help to prevent or reduce decision-making impairments in Parkinson’s disease patients.”
“Investigating how Parkinson’s disease medications affect decision-making will help the public to better understand the complexity of the disease and its treatment,” he added. “This will benefit patients, their families and carers, and motivate them to consider early care and preventive strategies.”
