The Connection Between Parkinson's Disease and Dopamine

Dopamine has been implicated as a major influencer of many behaviors and physical functions, including love, motivation, reward, pleasure, sleep, addiction, reproductive function, inflammation and pain, and immune function. It also plays a key role in initiating movement in the body.

Because of this, dopamine is largely regarded as a major contributor to Parkinson’s disease, a disease known to cause tremors, bradykinesia (slowed movement), muscle rigidity, and postural instability.

In this article, we will discuss the connection between Parkinson’s disease and dopamine, dopamine’s role in diagnosis, how to boost dopamine levels, and the future of Parkinson’s disease diagnosis.

Parkinson’s Disease and Dopamine

Parkinson’s disease is a progressive neurodegenerative disease that is most commonly known for affecting function and movement, though it also affects cognition, particularly as the disease progresses. Parkinson’s disease primarily impacts dopaminergic, or dopamine-producing, neurons in a specific area of the brain known as the substantia nigra. Dopamine is a key neurotransmitter that transmits signals between neurons and plays a key role in movement and motor control.

The lack of dopamine makes it difficult for the brain to coordinate muscle movements and can also contribute to mood and cognitive issues later in the disease course. Patients with Parkinson’s disease also lose nerve endings that produce norepinephrine, a chemical messenger of the sympathetic nervous system responsible for controlling a wide range of functions in the body, such as blood pressure and heart rate.

Although dopamine has been the primary neurotransmitter of focus—and is so far the most significant—Parkinson’s disease affects several chemical systems in the brain. The lack of dopamine causes several downstream effects on other neurotransmitters, such as Gamma-Aminobutyric Acid (GABA) and glutamate. 

Parkinson’s Disease and Dopamine: DaT/SPECT vs. PET

Typically, Parkinson’s disease is diagnosed “clinically,” meaning diagnosis is dependent on medical history, answers to certain questions, physical examination, and the presence of specific physical symptoms. There are no lab or imaging tests that can definitively diagnose Parkinson’s disease; however, there are several helpful imaging tools that can be used to analyze brain function and support Parkinson’s disease diagnosis: 

• DaT/SPECT: A dopamine transporter scan (DaTscan), a specific single-photon emission computerized tomography (SPECT) scan, can be used to visualize dopaminergic neurons. To do so, a radioactive tracer is injected into the bloodstream, where it then circulates the body, making its way to the brain. The drug binds to dopamine transmitters in the brain, producing detailed pictures of the dopamine system. DaT/SPECT is often used to help distinguish between other functional movement disorders, such as essential tremor.
• PET: While not approved by the FDA for Parkinson’s disease diagnosis, positron emission (PET) scans are commonly used during the diagnostic process to rule out other conditions. While the DaT/SPECT focuses on the activity of the dopamine transporter, PET scans typically focus on aspects like glucose metabolism.

How to Boost Dopamine

A large part of Parkinson’s disease treatment revolves around increasing dopamine levels in the brain—whether through dopamine-creating drugs, dopamine agonists, MAO B inhibitors, or lifestyle changes. Certain lifestyle changes can be incorporated to support brain health and promote dopamine production. Here is what experts recommend:

• Eat foods high in tyrosine: Tyrosine, an amino acid, is an essential component needed for the production of several important neurotransmitters, including dopamine. Dopamine is produced in the brain in two steps. First, an amino acid called tyrosine is converted into L-dopa. L-dopa is then converted to dopamine. By eating foods high in tyrosine, such as poultry, dairy, avocados, bananas, and sesame seeds, you may be able to boost dopamine levels in the brain.
• Engage in mood-promoting activities: Engaging in activities that make you feel relaxed or happy is also thought to increase dopamine levels. This could be meditating, exercising, spending time in nature, reading a book, listening to music, or whatever suits your fancy.