What Does Dopamine Do?
If you have Parkinson’s disease, anxiety, autism spectrum disorder (ASD), or another neurological condition, you may have heard about dopamine and how it can help you feel your best. But what does dopamine do, actually? Let’s dive into it.
What Is Dopamine?
Dopamine is a neurotransmitter your body uses to send messages between nerve cells. Your body produces dopamine from tyrosine, an amino acid found in many foods including chicken, pork, fish, cheese, soybeans, nuts, seeds, eggs, and whole grains. Your neurons use enzymes to convert tyrosine first into a substance called L-dopa and then into dopamine.
We often call dopamine “the feel-good hormone” because it plays a key role in your brain’s pleasure centers. This neurotransmitter is part of the body’s reward system, which influences motivation and behavior.
Dopamine helps guide motivation while we learn which aspects of life are pleasurable and which are painful. We also produce dopamine as a reaction to other pleasurable experiences like getting rewarded at work or doing well on a test. These dopamine signals reinforce the behavior that caused them.
For example, foods with higher levels of sugar typically cause a release of dopamine, which is why some people turn to food for comfort. Your brain remembers the rush of dopamine and motivates you to seek out more of it in cookies or other simple carbohydrates.
Dopamine also interacts with other neurotransmitters, such as serotonin, to regulate body functions. For example, serotonin can bind to receptors on neurons in the brain to affect dopamine release. These dopamine signals can affect motor control and thinking in addition to the reward system.
The precise relationship between dopamine and serotonin, as well as how they influence our behavior, is not fully yet understood. While both neurotransmitters are related to feelings of pleasure and well-being, they work differently. A simplistic explanation is that dopamine encourages you to seek out more of whatever is triggering its release, while serotonin motivates you to stop doing something that may result in “punishment.”
In addition to reward behaviors and mood, dopamine also plays a role in movement. The basal ganglia (a group of structures deep in the brain) and the substantia nigra (which produces dopamine) within the basal ganglia depend on dopamine to keep movements coordinated. When dopamine levels are low in this region of the brain, movement becomes slow, delayed, or uncoordinated. When dopamine is too high, it can cause unintended movements such as tics.
How Does Dopamine Work?
Dopamine is produced from tyrosine or L-dopa inside of certain neurons in the brain. It is released into the synapse between neurons in response to a neurological signal.
The released dopamine transmits signals from one neuron to the next within the synapse by binding to dopamine receptors on the outside of these neurons. These receptors govern different aspects of your body, including impulse control, memory, attention, sleep, motion, and even kidney function. The dopamine active transporter (DAT) can re-uptake dopamine from the synapse back into a neuron to stop the signal.
Your body has five different dopamine receptors. We’ll consider two of them here: DRD1 and DRD2. Both are abundant on the outsides of dopamine-sensitive neurons in the central nervous system and activate a dopamine signal cascade inside a neuron when they bind to dopamine.
Many of your brain’s dopamine receptors are in the striatum, a region that governs motivation and motor learning. This region is a large part of your motivation and reward center. Dopamine in this area can cause reward-seeking loops, motivating you to repeat pleasurable activities. Something as small as checking social media and seeing how many people engaged with your post causes a small surge of dopamine, which leads you to do it again and again.
Recent research in mice suggests that there are three different subtypes of dopamine-sensitive neurons. Two of these are activated in response to unexpected rewards as well as “punishments” (i.e. air puffs to the face, which mice dislike). The activation of a third subtype of dopamine-sensitive neurons, located primarily in the substantia nigra, occurs only when the animal moves, not in response to reward or punishment. This intriguing result suggests that dopamine-producing neurons affected by Parkinson’s disease are specific to movement.
What Happens When Dopamine Signaling Goes Awry?
Some people experience problems with their dopamine transporter and/or dopamine receptors. These issues can be genetic or caused by environmental influences like brain injuries or substance use/addiction. It’s also possible for the environment and behavior to influence your genetics (this is called epigenetics). While genetics are not the only reason dopamine signaling may be affected in a person, they are typically easier to study.
People with autism (ASD) may have differences in their dopamine signaling system. Some have dopamine transporter/receptor mutations that impact the natural balance of dopamine in their bodies.
Dysfunctional dopamine signaling may lead to neurological conditions and behavioral changes. For example, differences in genes encoding for DAT have been associated with risk for ADHD, and mutations in DAT have been identified in ASD. Additionally, challenges with motor control and sleep problems that commonly co-occur with autism may be due to problems with dopamine receptors.
ASD & Dopamine Signaling
If you are an Autistic person, your dopamine signaling or dopamine biosynthesis may be different from an allistic person's. Because of this, your brain might not process some experiences as “rewarding,” and you might not be motivated to do them again. Some researchers speculate that these differences in the way your body processes dopamine could impact your social experiences.
Because dopamine signaling may be dysregulated in autism, too much or too little dopamine may be present. It’s also possible that dopamine receptors may not respond with the appropriate level of activity to the amount of dopamine that is present within the synapse. Dysregulated dopamine can interfere with mood, sleep, and the ability to concentrate.
ADHD & the Role of Dopamine Receptors
The DRD2 gene is mutated in many people with ADHD. These DRD2 mutations can lead to fewer dopamine receptors on neurons, interfering with dopamine signaling. One model of ADHD suggests that there is too little dopamine activity in the prefrontal lobes, making it hard to concentrate, while at the same time there is too much dopamine activity in the basal ganglia, leading to motor hyperactivity or even motor tics.
Parkinson’s Disease & Dopamine Transmission
Other diseases can also impact the brain’s ability to transmit dopamine. As Parkinson’s disease progresses, it impacts the dopamine-producing cells of the substantia nigra. When too many of these cells die, patients with Parkinson’s start experiencing low amounts of dopamine, which causes motor symptoms, tremors, rigidity, and a loss of balance and coordination. Parkinson’s disease illustrates the important impact of dopamine on motor function.
How to Boost Dopamine Levels
If you suspect you have low levels of dopamine, you may wonder how to increase it. Fortunately, there are many ways to increase dopamine levels naturally, but it’s not as simple as taking a capsule full of dopamine.
Taking dopamine by mouth cannot have an effect on your brain, because dopamine can’t cross the blood-brain barrier. Your body has a complex blood vessel system that delivers oxygen and other essential nutrients to your brain. However, these blood vessels also protect your brain by making it hard for many molecules and pathogens to pass through this barrier.
Because of the blood-brain barrier, you need to instead boost your body’s ability to make dopamine. Here are some strategies that may help:
Use Dopamine-Enhancers
Certain herbs, vitamins, and amino acids may support how your body produces and metabolizes dopamine by providing more of a component you need to make it (e.g., B6, tyrosine). Others work to increase the ability of existing levels of dopamine to transmit a nerve signal, or to prevent the reuptake of dopamine from the nerve synapse. You can learn more about dopamine-enhancers here.
If you have a medical condition or take meds that affect dopamine, consult with your health care provider before taking another substance that also affects dopamine.
Consider Psychobiotics
Special probiotic strains called psychobiotics appear to have the ability to affect the activity of neurotransmitters like serotonin. However, L. plantarum PS128 may be the only psychobiotic that has been shown to change the levels of dopamine within the brain (in animal studies).
While dopamine can't be easily measured in the brains of humans, a small single-arm pilot study suggested that some people who took PS128 in combination with their existing Parkinson's treatment saw improved motor control after 8 weeks. Additional studies of PS128 in Autistic people suggests a potential benefit for anxiety and focus.
Embrace Lifestyle Changes
Lifestyle changes can also impact your body’s ability to produce dopamine and use it effectively as a neurotransmitter. For example, exercise supports healthy levels of dopamine.
You can also enhance your ability to produce brain dopamine by stocking up on its building blocks, namely tyrosine. Eating foods like meats, fish, soy, low-fat dairy, and other foods high in tyrosine gives your body more of what it needs to create dopamine.
Interestingly, a 2017 study found that people who habitually ate foods high in tyrosine scored higher for two measures of cognition than those who did not, and this effect was equally strong for young and old participants.
You can stimulate dopamine production in your body by getting enough sleep. When you’re busy, it’s easy to cut down on rest to get things done. Stress and anxiety can also impede your ability to fall or stay asleep.
Sleep deprivation can decrease dopamine receptors, decreasing dopamine signal transmission. This is one possible explanation for why people have so much trouble concentrating when they sleep poorly. Not sleeping can also make you more impulsive, which is another sign of abnormal levels of dopamine.
Your Connection to Dopamine
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