What Is Dopamine?
A neurotransmitter and important signaling molecule
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Medically reviewed by Nicholas R. Metrus, MD
Dopamine is a neurotransmitter, one of the brain’s important signaling molecules. It plays a role in an incredible number of brain functions. However, dopamine’s role in human health is even more complicated than that. Dopamine is also produced locally at multiple other places in the body, such as the eyes, pancreas, and cardiovascular system.
This article discusses how dopamine works in the brain and the rest of the body. You’ll also learn about how dopamine systems are altered in some medical conditions, as well as some of the dopamine-related medications used to treat them.
How Does Dopamine Affect You?
Dopamine is made in the body before other similar substances like norepinephrine and epinephrine, which are also neurotransmitters. It affects the way these and other neurotransmitters act. Understanding dopamine is also complicated because it interacts with so many other signaling processes in the brain.
Certain neurons in the brain produce dopamine. Under certain circumstances, they release that dopamine, which sends a message to other nearby cells. That released dopamine can bind to different types of dopamine receptors on neighboring cells. Depending on the type of receptor, this has different effects on the cell, many of which are quite complicated.
The effect of dopamine also varies based on where in the brain the dopamine is released, sometimes called “dopaminergic pathways.” Partly depending on the pathways and receptors involved, dopamine has a role in the following:
Movement and motor control
Learning with pleasurable reinforcement
Attention and cognition
Mood
Impulse control
Sleep and arousal
Nausea
Hormone regulation (e.g., for lactation hormones)
However, dopamine also affects other tissues of the body outside the brain, although some of this is not as well understood. For example, dopamine receptors can be found in the following:
Cardiovascular system
Gastrointestinal system, e.g., the pancreas
Immune system
Retina (nerve tissue in the eye)
Dopamine’s Reward Pathway
You might have heard that dopamine is associated with your sense of pleasure. After a rewarding experience, dopamine is released in some parts of the brain. That’s part of how your brain learns that a certain experience is positive.
Previously, scientists theorized that the release of dopamine itself might be part of the pleasurable feeling associated with such activities, and this idea became fairly widespread in the public.
We still think that dopamine interacts with other brain chemicals, like serotonin, that are more directly responsible for pleasure. However, scientists now believe that dopamine itself isn’t responsible for these pleasurable feelings. Instead, dopamine plays a role in reinforcing such behaviors and motivating people to seek them out again.
For example, a release of dopamine might be stimulated by:
Food
Exercise
Winning a game
Listening to music you enjoy
Shopping
Using social media
Sex
Gambling
In addition, many different drugs affect the dopamine pathway (in addition to other parts of the brain). These include:
Nicotine
Caffeine
Alcohol
Heroin, cocaine, and certain other illicit drugs
These drugs affect the dopaminergic pathways in different ways and to different degrees.
Dopamine in Medical Conditions
The dopamine system in the brain is very complicated, and various imbalances in dopamine signaling and transmission play a role in several different neurological and psychiatric disorders. There is a lot we are still trying to understand about many of these connections.
Parkinson’s Disease
Of medical conditions related to changes in dopamine, Parkinson’s disease is perhaps the most straightforward. Parkinson’s, the most common neurodegenerative movement disorder, affects many of the neurons in an area of the brain called the substantia nigra.
These neurons normally produce dopamine, but Parkinson’s disease causes many of them to die. Because of that, the brain can’t produce as much dopamine as it normally would.
This affects the activity of the different areas of the brain which normally have dopamine signaling. It results in symptoms like depression and cognitive impairment, as well as problems with movement such as tremors, rigidity, and slower-than-normal movement.
Schizophrenia
For several decades researchers have known that dopamine pathways are affected in people with schizophrenia. Originally scientists believed that hyperactivity of certain dopamine pathways led to symptoms of schizophrenia, such as hallucinations and delusions. For example, this might be due to increased release of dopamine and increased activation of certain types of dopamine receptors.
However, scientists now also think that people with schizophrenia may have an underactivity of certain dopamine pathways. For example, reduced dopamine and reduced activity of dopamine receptors in some parts of the brain may be a part of other symptoms of schizophrenia, such as a lack of motivation and reduced pleasure.
Depression and Bipolar (Manic) Depression
Although historically depression has been more linked to changes in other neurotransmitters such as serotonin, we also think that the dopamine system is affected. For example, reduced dopamine levels in certain brain regions may be part of why people with major depressive disorder might not actively seek out activities they used to find pleasurable.
However, in people with bipolar depression, the situation is more complicated. They may also have lower levels of dopamine in certain areas of the brain during depressive periods. However, when these people are experiencing mania and abnormally elevated mood, it may be partly due to greater activity of certain types of dopamine receptors.
Restless Legs Syndrome
Some sort of dopamine dysregulation seems to play a role in restless legs syndrome, a condition more common in people with Parkinson’s disease. Reduced numbers of certain dopamine receptors and decreased activity in certain dopamine pathways may be part of what causes the strong, uncomfortable urge to move one’s legs.
ADHD
Attention-deficit/hyperactivity disorder (ADHD) can cause symptoms like hyperactivity, inattentiveness, and mood swings. Since we know that dopamine plays a role in these qualities, it’s perhaps not surprising dopamine dysregulation is found in this condition.
However, it’s complex. Certain areas of the brain may have more dopamine stimulation than they need, but others might not have enough. Scientists are still trying to figure out how various alterations in dopamine might fit in with other brain changes in ADHD.
Addiction
Changes in the dopamine system are also found in people dealing with addiction. Dopamine levels in certain parts of the brain increase in response to a drug or a pleasurable experience, which may contribute to cravings. Dopamine is part of what makes you seek out circumstances where you can repeat the experience, especially in people with an addiction.
Over the long term, people with addiction develop changes to the dopaminergic system such as decreases in the number of certain receptors for dopamine. This is why a person may need higher doses of a drug over time to get the same initial feeling.
Dopamine as Medicine
Medicines affecting dopamine are used to treat many kinds of medical conditions.
Inotropin (Dopamine)
Dopamine itself isn’t used very often as a medication. That’s partly because if you give a person dopamine through a pill or through the blood, it doesn’t make it into the brain, where it’s usually needed.
One important exception is dopamine given through an intravenous (IV) line. This is sold under the brand name Intropin, among others.
Dopamine can be helpful in certain medical crisis situations because of the effects it has on the blood vessels. For example, it might be used if a person has very low blood pressure or a very low heart rate (bradycardia). It may also be used to try and restart the heart of someone in cardiac arrest.
Dopamine Precursors
To get dopamine into the brain, scientists learned that they could use a substance called levodopa, a chemical precursor to dopamine. Taken in the form of a pill, it can get through to the brain, where it is converted to dopamine. Levodopa is a cornerstone of treatment for Parkinson’s disease.
Scientists also learned that levodopa often worked best when paired with carbidopa, a drug that helps prevent the breakdown of levodopa. This allows healthcare providers to give a lower dose of levodopa, so it can cause fewer side effects like nausea.
Agents That Increase Dopamine Signaling
Scientists also developed medications that work to trigger certain types of dopamine receptors. The idea was that this could provide more targeted therapy for symptoms of Parkinson’s while reducing side effects. In people with Parkinson’s disease, these may be used early in the disease, or they may be combined with levodopa and carbidopa.
Examples of drugs in this class are Mirapex (pramipexole), Requip (ropinirole), and Neuropro (rotigotine). These drugs can also be used to treat restless legs syndrome.
Another important drug in this class is Cycloset (bromocriptine), which is FDA-approved to treat type 2 diabetes. That’s because part of your brain, the hypothalamus, releases dopamine, which has effects like better sensitivity to insulin.
Related:Pros and Cons of Dopamine Agonists and Other Treatments for Restless Leg Syndrome
Dopamine Blockers
Instead of increasing the effects of dopamine, another class of drugs works to block them. Such drugs are often very helpful in treating schizophrenia. For example, classic dopamine blockers used to treat it include Haldol (haloperidol) and Thorazine (chlorpromazine).
Such medications are also sometimes used to treat mania as part of bipolar disorder. Healthcare providers also sometimes treat bipolar disorder with medications that block dopamine in certain brain pathways while stimulating it in others, like Seroquel (quetiapine).
Dopamine-blocking drugs can also be used to temporarily treat excess nausea and vomiting (during chemotherapy treatment). Compro (prochlorperazine) and Inapside (droperidol) are examples of important drugs in this class.
Other Drugs with Dopamine Effects
A variety of other drugs also affect dopamine signaling while affecting other neurotransmitters and brain signaling pathways at the same time. For example, the antidepressant Wellbutrin (bupropion) partly works by increasing the amount of dopamine stimulation some cells receive. Wellbutrin is also sometimes used to help people reduce their cravings and quit smoking.
Stimulants such as methylphenidate are another example. These drugs increase available levels of dopamine and other neurotransmitters and are a critical part of treatment for ADHD.
How To Increase Your Dopamine Levels
Although finding ways to naturally “boost one’s dopamine” is a popular idea in the health world, it’s not necessarily a helpful concept. As discussed, dopamine circuitry is complex, and much of it is not completely understood.
Some people might benefit from more or less dopamine in certain parts of their brain or better dopamine regulation. But it’s quite complicated, with many potentially different underlying causes, and we don’t always understand the difference between causes and effects.
Moreover, blood tests for dopamine are rarely used, as they usually don’t give much helpful information. Dopamine deficiency isn’t a condition that healthcare providers diagnose. So dopamine is quite different from other tests that might give you information about your overall health.
However, there’s nothing wrong with finding the activities and habits that may boost your mood and your overall sense of long-term well-being. You want activities that don’t just give you a temporary jolt, like you might get from addictive substances, but ones that can help lead to more enduring mental health.
A prime example is exercise. People who regularly exercise may have higher baseline levels of dopamine on average, with exercising triggering further dopamine production. But perhaps more importantly, regular exercise can have a positive effect on mood and overall mental health, whether through dopamine, other neurotransmitters like serotonin, or multiple other effects.
You probably already know the other activities in your life that make you feel better when you do them long-term. Whether it’s eating a balanced diet, socializing with friends, getting enough sleep, meditating, or taking time for a hobby you enjoy, you can help prioritize your mental well-being.
Related:Find Deeper Happiness
A Quick Review
Dopamine is a critical signaling molecule in the brain, one that plays key roles in movement, attention, mood, and reinforcing pleasurable experiences. People with Parkinson’s disease have lower than normal levels of dopamine at various brain sites. But dopamine may also be dysregulated in several other disorders, and dopamine-related medications can treat a variety of health conditions.
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Read the original article on Health.
