New research reveals that the brains movement circuits are remarkably durable to the loss of dopamine, a chemical crucial for movement, in the asymptomatic period of Parkinsons illness. The study discovered that mice showed normal motion capacity in spite of nearly no active dopamine secretion, recommending that only low basal levels of dopamine are required for brain activity, and signs of Parkinsons appear when a minimum threshold is gone beyond.
Were you or an enjoyed one just recently diagnosed with Parkinsons illness? New research study shows that the disease might have been advancing quietly but insidiously for more than 10 years.
This research study, performed at the University of Montreal and published in the journal Nature Communications, offers new insights into the unexpected durability of the brain during the asymptomatic duration of Parkinsons.
In their study, a group led by UdeM neuroscientist Louis-Éric Trudeau showed that movement circuits in the brains of mice are insensitive to an almost overall loss of active secretion of this chemical messenger.
This observation is unexpected because dopamine is a chemical messenger recognized for its importance in motion. And in Parkinsons disease, dopamine levels in the brain drop inexorably.
” This observation went versus our preliminary hypothesis, but thats typically the way it remains in science, and it forced us to re-evaluate our certainties about what dopamine really performs in the brain,” said Trudeau, a professor in UdeMs Department of Pharmacology and Physiology and Department of Neurosciences.
Using genetic adjustments, Trudeau and his researchers removed the ability of dopamine-producing neurons to launch this chemical messenger in action to the regular electrical activity of these cells.
As a doctoral student in Trudeaus laboratory, Benoît Delignat-Lavaud anticipated to see a loss of motor function in these mice comparable to what is seen in people with Parkinsons.
Surprise! The mice showed a totally typical capability for movement.
Measuring dopamine levels
On the other hand, measurements of overall dopamine levels in the brain, carried out by UdeM injury expert Louis de Beaumonts group at the Centre de recherche de lHôpital du Sacré-Cœur de Montréal, exposed that extracellular levels of dopamine in the brain of these mice were regular.
These results recommend that the activity of movement circuits in the brain needs just low basal levels of dopamine.
It is for that reason likely that in the early stages of Parkinsons disease, basal dopamine levels in the brain stay sufficiently high for lots of years– this, despite the steady loss of dopamine-producing neurons. It is only when a minimum threshold is gone beyond that motor perturbations appear.
According to the researchers, by identifying the systems involved in the secretion of dopamine in the brain, this advance in Parkinsons research could help to identify brand-new techniques to reduce the signs of this incurable neurodegenerative illness.
Reference: “Synaptotagmin-1-dependent phasic axonal dopamine release is dispensable for fundamental motor habits in mice” by Benoît Delignat-Lavaud, Jana Kano, Charles Ducrot, Ian Massé, Sriparna Mukherjee, Nicolas Giguère, Luc Moquin, Catherine Lévesque, Samuel Burke, Raphaëlle Denis, Marie-Josée Bourque, Alex Tchung, Pedro Rosa-Neto, Daniel Lévesque, Louis De Beaumont and Louis-Éric Trudeau, 11 July 2023, Nature Communications.DOI: 10.1038/ s41467-023-39805-7.