Scientists have found a new treatment for Parkinson's disease

Photo Source: Johns Hopkins University
In a new study of seven Parkinson's patients, using electrical impulses for deep brain stimulation can quickly activate nerve cells that secrete the chemical messenger dopamine, reducing tremors and muscle stiffness , a hallmark of Parkinson's disease, and increasing happiness.
" Although deep brain stimulation has been used to treat Parkinson's disease for more than 30 years, its mechanism of action is not yet fully clear. Gwenn Smith, professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine, said, "Our study is the first to show in human subjects with Parkinson's disease that deep brain stimulation may increase dopamine levels in the brain, which may be part of the reason for the improvement in symptoms in these people." The
their findings were published in The Journal of Parkinson's disease and related diseases.
parkinson's disease is a neurodegenerative disease that affects about 10 million people worldwide, most of them over the age of 50, according to the National Institutes of Health. The disease is caused by the gradual death of nerve cells that secrete the neurotransmitter dopamine. Symptoms usually worsen over time, affecting exercise and mental health.
when dopamine-enhancing drugs do not relieve the symptoms of Parkinson's disease, deep brain stimulation is usually the next treatment. In a process similar to implanting a pacemaker, surgeons implant wires connected to a power supply and send tiny electrical vibrations through brain tissue to alter the way nerve cells discharge. Usually, to treat Parkinson's disease, electrons are sent into the brain to receive chemical information from dopamine secretion cells, rather than the cells themselves that secrete dopamine.
most of the understanding of how electrical stimulation alters brain activity in people with Parkinson's disease comes from PET imaging. PET scans detect signals from radioactive tracer agents, which are combined with specific molecules in the body. Previous PET imaging studies using glucose tracer have shown an increase in metabolism in the brain after electrical stimulation, indicating that treatment restores normal brain activity. However, PET studies using tracer agents that bind to targets or recipients on dopamine receiving cells showed no change in dopamine levels after electrical stimulation, suggesting that dopamine may not have a role in improving brain activity, and may not have any effect on alleviating symptoms of Parkinson's disease.
but scientists suspect dopamine may still play a key role in successful deep brain stimulation.
we know that dopamine secretion cells are connected to many parts of the brain. Kelly Mills, assistant professor of neurology at Johns Hopkins University School of Medicine, said, "So even if the cells that secrete dopamine are not directly activated, electrical stimulation of other parts of the brain, especially those that receive information from dopamine secretion cells, can indirectly increase the secretion of dopamine, but there is a general lack of evidence in patients." To
to more accurately study changes in dopamine levels after deep brain stimulation, the researchers studied a protein called vesicle monoamine transporter VMAT2. VMAT2 captures free-floating dopamine molecules and places them in biopics called follicles, which release their contents toward nerve endings.
VMAT2 PET scans in people with Parkinson's who took dopamine-enhancing drugs showed that dopamine was associated with VMAT2: as taking zodopa increased dopamine levels in the brain, VMAT2 levels dropped and vice versa.
to see if deep brain stimulation increased dopamine, the researchers used VMAT2 tracer to perform PET scans on people with Parkinson's disease. They also performed PET scans using glucose tracer to assess changes in brain activity after intervention. The study involved three white women and four white men between the ages of 60 and 74. These patients received PET scans before and after deep brain stimulation. The researchers also assessed the movement and psychological symptoms of patients before and after electrical stimulation.
researchers found that after deep brain stimulation, the number of tremors in people with Parkinson's disease decreased significantly and stiffness decreased. The patient's cognitive and emotional abilities also improved, with a 40 percent drop in depression scores.
analysis of PET scans, the researchers found that all seven patients had lower levels of VMAT2 after deep brain stimulation, which meant higher levels of dopamine in the brain. Glucose PET scans showed that after electrical stimulation, the brains of these patients improved their activity in the coordinated movement, mood, and cognitive regions. In addition, Mills said, VMAT2 and glucose PET scans correspond to each other, suggesting that the increase in dopamine may be one of the key mechanisms for brain activity to return to normal after electrical stimulation.
we can see dopamine levels rise because we've changed the way we look at it," he said. Mills said. (Source: China Science Journal Zhao Xixi)
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