How Parkinson's Affects Dopamine
- Neurology Associates
- 11 minutes ago
- 4 min read
When Muhammad Ali's hands began to tremble and his once lightning-quick movements slowed, the world witnessed the effects of Parkinson's disease on one of history's greatest athletes. At the core of this devastating condition lies a profound disruption in the brain's dopamine system – a disruption that transforms lives and challenges medical science.
Recent research has dramatically reshaped our understanding of how Parkinson's disease affects dopamine in the brain, revealing that what was once considered a straightforward chemical deficiency is actually an intricate neurological puzzle.
The relationship between Parkinson's disease and dopamine remains central to both diagnosis and treatment approaches, but scientists now recognize this relationship is far more complex – and promising – than previously thought.
What Happens to Dopamine Neurons in Parkinson's Disease?
In people with Parkinson's disease, nerve cells that produce dopamine slowly die. This progressive destruction of dopamine-containing neurons, especially those controlling movement, leads to the characteristic symptoms of the disease. "The loss of dopamine leads to slower movements, resting tremors, and other symptoms that worsen over time," according to a 2019 Yale University study published in the journal Neuron.
This fundamental relationship between dopamine loss and Parkinson's symptoms was first established in the 1960s. "Oleh Hornykiewicz, a pharmacologist, was among a handful of scientists to identify a deficiency of the neurotransmitter dopamine as a cause of Parkinson's disease," notes a recent New York Times article on Parkinson's disease and head injuries. This scientific discovery proved crucial for developing the treatments we rely on today.
How Dopamine Levels Drop Affects Movement and Beyond
When dopamine levels drop in Parkinson's disease, the effects extend far beyond just pleasure and reward systems. Dr. Maia Szalavitz, contributing Opinion writer at The New York Times who covers addiction and public policy, explains: "Dopamine also affects neural circuits that control movement.
That's why a genuine dopamine fast would be a terrible idea. People with Parkinson's disease know this firsthand: Their condition is caused by the progressive destruction of dopamine-containing neurons, especially those controlling movement. This causes tremors and difficulty moving."
The decline in dopamine typically manifests through several movement-related symptoms:
Resting tremors (although about 20% of patients don't experience this)
Stiffness or rigidity in limbs and trunk
Bradykinesia (slowness of movement)
Shuffling gait
Decreased facial expression ("masked face")
Softer, sometimes trailing voice
These motor symptoms highlight how Parkinson's disease affects dopamine pathways controlling physical movement, but the impact extends to cognitive and emotional functions as well.
The Role of Dopamine in Parkinson's: More Complex Than We Thought
While researchers have long known how Parkinson's disease affects dopamine production, recent studies suggest the neurobiology is more complicated.
"Whatever the causes, the brains of Parkinson's patients generally start to show a deficit in three neurotransmitters: serotonin, dopamine, and acetylcholine," explains Dr. Michael Okun, director of the Fixel Institute for Neurological Diseases at the University of Florida and medical adviser to the Parkinson's Foundation.
The conventional view that dopamine deficiency alone drives Parkinson's symptoms is evolving. A groundbreaking Yale study found that "the reduction in dopamine decreases the activity of a small population of cells within the striatum that are responsible for making acetylcholine. While the concentrations of both dopamine and acetylcholine decline, the balance between these two neurotransmitters shifts to favor acetylcholine."
This research challenges the previous assumption that "when dopamine levels dropped, acetylcholine levels increased," revealing instead that both neurotransmitters actually decline, but their balance changes.
How is Dopamine Transporter Imaging Used in Diagnosis?
Measuring how Parkinson's disease affects dopamine systems has become an important diagnostic tool. According to TIME magazine's recent coverage, "Magnetic resonance imaging (MRI) or a dopamine transport scan of the brain—in which a radioactive tracer that attaches itself to dopamine receptors is injected into the blood—can also help confirm the diagnosis."
This dopamine transporter (DAT) scan provides visual evidence of dopamine activity in the brain, helping physicians distinguish Parkinson's from other movement disorders that may present with similar symptoms but don't affect dopamine systems in the same way.
Can We Boost Dopamine Levels to Treat Parkinson's?
The primary treatment approach for Parkinson's continues to focus on addressing how Parkinson's disease affects dopamine production. "Dr. Hornykiewicz and his assistant then developed a treatment with L-dopa, a chemical precursor to dopamine," which remains the foundation of Parkinson's treatment today.
Dr. Vikas Kotagal, an associate professor of neurology at the University of Michigan, confirms this enduring approach: "L-dopa, or Levodopa, is still a mainstay treatment for Parkinson's disease, especially in the early stages." This medication works by converting to dopamine in the brain, helping to restore the chemical balance disrupted by the disease.
In addition to levodopa, other medication strategies attempt to boost dopamine function through different mechanisms. "There are other drugs that go straight to the dopamine receptors and sort of tickle the receptors," says Dr. Okun. "These are called dopamine agonists."
Dr. Kotagal explains that levodopa "can help patients with their speed of walking and fine motor skills — like buttoning buttons, zipping zippers and holding utensils," directly connecting dopamine replacement to improved physical functioning.
However, managing dopamine replacement becomes increasingly complex as the disease progresses. "In later stages of the disease, Dr. Kotagal said, treatment consists mainly of administering as much Levodopa as is helpful without getting disabling side effects."
Specialized Care for Dopamine-Related Parkinson's Treatment
Neurology Associates Neuroscience Center at Chandler and Mesa locations offers comprehensive evaluation and management of Parkinson's disease, including assessment for deep brain stimulation therapy. Our team provides personalized care plans with flexible appointment options, including telemedicine consultations for qualifying patients. We collaborate with specialists to ensure patients have access to advanced treatment options for managing how Parkinson's disease affects dopamine systems and related neurological functions.
IMPORTANT NOTE: This blog post is for informational purposes only and not medical advice. Always consult a qualified healthcare provider for diagnosis or treatment. Do not rely on this content as a substitute for professional medical guidance.
