Parkinson’s Disease: Brain Resilience Uncovered in Mice Study

According to a mouse study, Parkinson’s disease can grow quietly but insidiously for many years before the neurodegenerative disease is recognised. The study, which was just published in the journal Nature Communications, gives new information on the brain’s astonishing resiliency throughout the asymptomatic phase of Parkinson’s disease.
The researchers from the University of Montreal in Canada discovered that movement circuits in mice brains are insensitive to a nearly entire loss of active dopamine release, a chemical messenger known for its involvement in movement. Dopamine levels in the brain diminish inevitably in Parkinson’s disease, they claim. “This observation contradicted our initial hypothesis, but that’s often the case in science,” said Louis-Eric Trudeau, a professor at the University of Montreal. “It forced us to re-evaluate our certainties about what dopamine really does in the brain.”

The scientists used genetic alterations to prevent dopamine-producing neurons from releasing this chemical messenger in response to normal electrical activity in these cells. The researchers, notably Benoit Delignat-Lavaud, a doctorate student in Trudeau’s laboratory, expected to find motor function decrease in these mice, comparable to what is seen in Parkinson’s patients.

Surprisingly, the mice demonstrated entirely normal mobility abilities, according to the researchers. Measurements of total dopamine levels in the brain revealed that extracellular dopamine levels in the brains of these mice were normal, according to the researchers. They concluded that the functioning of movement circuits in the brain required only modest basal levels of dopamine.

The researchers concluded that, in the early stages of Parkinson’s disease, baseline dopamine levels in the brain are likely to remain adequately high for many years, despite the steady loss of dopamine-producing neurons. Motor disturbances arise only when a minimum threshold is exceeded, they claim. The researchers hope that by pinpointing the systems involved in dopamine secretion in the brain, they may be able to uncover new techniques to alleviate the symptoms of this incurable neurodegenerative disease.