A study conducted by researchers at McGill University and published on Nature Neuroscience challenged a long-standing idea, namely how dopamine (a neurotransmitter) influences movement. These findings could pave the way for a better understanding and new treatments of morbo in Parkinson’s.
What is Parkinson’s disease
Parkinson’s disease is a neurodegenerative disorder slow but progressive evolution. It is characterized by the neurodegeneration of neurons in the substantia nigra, a small area of the central nervous system. Their job is to produce the dopaminea molecule essential for movement control and posture.
In 70% of cases those suffering from the pathology are those with over 65 years oldespecially men. Episodes with young onset are rare (in fact they represent around 5% of diagnoses) and are almost always considered genetically determined.
Causes: hereditary forms and genetic mutations
The precise causes of the disease are still unknown, however science agrees on its multifactorial genesis. From a genetic point of view, hereditary forms have been identified (10-15% of casesi) caused by mutation of certain genes: Parkin, Alpha-synuclein, Glucocerebrosidase, PINK1, DJ1, LRRK2-dardarin.
A relationship has also been noted between the onset of Parkinson’s and some environmental factors. These include the lifestyle (cigarette smoking, unbalanced diet) andexposure to toxic substances (heavy metals, pesticides, insecticides, hydrocarbons, industrial and agricultural chemicals).
Finally, let’s not forget the role of endogenous factors. These include the accumulation of iron in the substantia nigra, oxidative stress, mitochondrial dysfunction and the phenomenon of excitotoxicity.
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morbo in Parkinson’s
The role of dopamine in Parkinson’s disease
The neurotransmitter dopamine It significantly influences the strength and speed of movements. In Parkinson’s patients, the brain cells that produce it degrade over time. This results in the typical symptoms, namely slowness, tremors and balance problems.
Currently the levodopa it is the treatment of choice to restore movement, increasing dopamine levels in the brain. However, the precise mechanism through which the drug exerts its effects is not yet completely clear. In recent years, brain monitoring tools have detected brief fluctuations in dopamine levels during movement.
It was thus hypothesized that the neurotransmitter could directly control the intensity and vigor of movements. In reality, new discoveries have called this hypothesis into question.
The study
Scientists at McGill University have come to the conclusion that dopamine does not act as a motion controller moment by moment. To test this hypothesis the team monitored the mice’s brain activity while the animals pressed a heavy lever. Using a light-based method, they were able to turn dopamine-producing cells on or off during the task.
According to the initial hypothesis, changes in dopamine levels they would have to change the speed or the strength of the rodents’ movements. In reality the regular dopaminergic activity during movement it made no difference. The researchers then tested levodopa and found that the drug improved movement by increasing the overall level of dopamine in the brain, rather than by modulating rapid fluctuations during action.
Towards more targeted treatments
According to researchers the most detailed understanding of how levodopa works could guide the development of future treatments focused on maintenance of stable levels of dopamine.
The results of the analysis also encourage scholars to revisit older treatment strategies.
In the past the agonists of dopamine receptors they showed benefits, however they caused annoying side effects.
The new insight could therefore help the team design safer therapies that act selectively. Further investigations are needed.
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