How Parkinson’s disease can grow undetected for years

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Imagine someone you know has just been diagnosed with Parkinson’s disease. You may be shocked to hear that the disease has probably been quietly progressing in their body for over a decade.

Yes, that’s right. More than ten years before any signs showed up. This was found in a recent study at the Université de Montréal. The research was published in a journal called Nature Communications.

The study gave new insights into how our brains resist the effects of Parkinson’s disease during the period when there are no symptoms. This period is also called the asymptomatic period.

The Mystery of Dopamine

A team of researchers led by a scientist named Louis-Éric Trudeau from UdeM conducted this study.

They focused on how the movement circuits in the brains of mice react to a big decrease in the release of a chemical messenger. This chemical messenger is called dopamine.

Why dopamine? Because it’s known to be very important for movement. And in Parkinson’s disease, the amount of dopamine in the brain keeps going down.

But what they found was surprising. The movement circuits in the mice’s brains didn’t react much to the big decrease in dopamine. T

his finding surprised the scientists because it went against their initial thoughts. But they had to accept it and rethink what dopamine really does in the brain, according to Trudeau.

Surprising Mice Experiment Results

Trudeau’s team used genetic manipulations for their experiment.

They made the dopamine-producing neurons in the mice’s brains lose their ability to release dopamine. They did this in response to the normal electrical activity of these cells.

Benoît Delignat-Lavaud, a doctoral student in Trudeau’s laboratory, was expecting to see a loss of motor function in these mice. This is similar to what happens in people with Parkinson’s disease.

But what happened? The mice had completely normal movement. This was another surprising observation.

Checking Dopamine Levels

Meanwhile, another team measured the overall levels of dopamine in the brains of the mice. Louis de Beaumont, a trauma specialist at UdeM, led this team at the Centre de recherche de l’Hôpital du Sacré-Cœur de Montréal.

They found that the levels of dopamine outside the cells (extracellular levels) in the brains of these mice were normal. This suggests that the activity of movement circuits in the brain only needs low levels of dopamine.

So, what happens in the early stages of Parkinson’s disease? The basic levels of dopamine in the brain probably stay high enough for many years, even as the number of dopamine-producing neurons goes down.

It’s only when these dopamine levels drop below a certain level that problems with movement (motor perturbations) start to appear.

How This Can Help Us

This new understanding of how dopamine works in the brain could help in Parkinson’s research.

By figuring out the mechanisms involved in the release of dopamine in the brain, scientists could find new ways to reduce the symptoms of this incurable disease that causes the brain to degenerate.

If you care about Parkinson’s disease, please read studies about a big cause of Parkinson’s disease, and natural killer cells could halt Parkinson’s progression.

For more information about cognitive health, please see recent studies about new drug that may slow or reverse age-related cognitive decline, and results showing that high blood pressure in young adulthood linked to cognitive decline in middle age.

The study was published in Nature Communications.

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