Neurotransmitters are chemical messengers in the body. Their job is to transmit signals from nerve cells to target cells. These target cells may be in muscles, glands, or other nerves.
The brain needs neurotransmitters to regulate many necessary functions, including:
- heart rate
- sleep cycles
- muscle movement
The nervous system controls the body’s organs, psychological functions, and physical functions. Nerve cells, also known as neurons, and their neurotransmitters play important roles in this system.
Nerve cells fire nerve impulses. They do this by releasing neurotransmitters, which are chemicals that carry signals to other cells.
Neurotransmitters relay their messages by traveling between cells and attaching to specific receptors on target cells.
Each neurotransmitter attaches to a different receptor — for example, dopamine molecules attach to dopamine receptors. When they attach, this triggers action in the target cells.
After neurotransmitters deliver their messages, the body breaks down or recycles them.
Key types of neurotransmitters
Many bodily functions need neurotransmitters to help communicate with the brain.
Experts have identified more than 100 neurotransmitters to date.
Neurotransmitters have different types of action:
- Excitatory neurotransmitters encourage a target cell to take action.
- Inhibitory neurotransmitters decrease the chances of the target cell taking action. In some cases, these neurotransmitters have a relaxation-like effect.
- Modulatory neurotransmitters can send messages to many neurons at the same time. They also communicate with other neurotransmitters.
Some neurotransmitters can carry out various functions, depending on the type of receptor that they are connecting to.
The following sections describe some of the best-known neurotransmitters.
Acetylcholine triggers muscle contractions, stimulates some hormones, and controls the heartbeat. It also plays an important role in brain function and memory. It is an excitatory neurotransmitter.
Low levels of acetylcholine are linked with issues with memory and thinking, such as those that affect people with Alzheimer’s disease. Some Alzheimer’s medications help slow the breakdown of acetylcholine in the body, and this can help control some symptoms, such as memory loss.
Having high levels of acetylcholine can cause too much muscle contraction. This can lead to seizures, spasms, and other health issues.
The nutrient choline, which is present in many foods, is a building block of acetylcholine. People must get enough choline from their diets to produce adequate levels of acetylcholine. However, it is not clear whether consuming more choline can help boost levels of this neurotransmitter.
Choline is available as a supplement, and taking high doses can lead to serious side effects, such as liver damage and seizures. Generally, only people with certain health conditions need choline supplements.
Dopamine is important for memory, learning, behavior, and movement coordination. Many people know dopamine as a pleasure or reward neurotransmitter. The brain releases dopamine during pleasurable activities.
Dopamine is also responsible for muscle movement. A dopamine deficiency can cause Parkinson’s disease.
A healthful diet may help balance dopamine levels. The body needs certain amino acids to produce dopamine, and amino acids are found in protein-rich foods.
Meanwhile, eating high amounts of saturated fat can lead to lower dopamine activity, according to research from 2015. Also, certain studies suggest that a deficiency in vitamin D can lead to low dopamine activity.
While there are no dopamine supplements, exercise may help boost levels naturally. Some research has shown that regular exercise improves dopamine signaling in people who have early stage Parkinson’s disease.
The body may release endorphins during laughter.
Endorphins inhibit pain signals and create an energized, euphoric feeling. They are also the body’s natural pain relievers.
One of the best-known ways to boost levels of feel-good endorphins is through aerobic exercise. A “runner’s high,” for example, is a release of endorphins. Also, research indicates that laughter releases endorphins.
Endorphins may help fight pain. The National Headache Foundation say that low levels of endorphins may play a role in some headache disorders.
A deficiency in endorphins may also play a role in fibromyalgia. The Arthritis Foundation recommend exercise as a natural treatment for fibromyalgia, due to its ability to boost endorphins.
Also known as adrenaline, epinephrine is involved in the body’s “fight or flight” response. It is both a hormone and a neurotransmitter.
When a person is stressed or scared, their body may release epinephrine. Epinephrine increases heart rate and breathing and gives the muscles a jolt of energy. It also helps the brain make quick decisions in the face of danger.
While epinephrine is useful if a person is threatened, chronic stress can cause the body to release too much of this hormone. Over time, chronic stress can lead to health problems, such as decreased immunity, high blood pressure, diabetes, and heart disease.
People who are dealing with ongoing high levels of stress may wish to try techniques such as meditation, deep breathing, and exercise.
Anyone who thinks that their levels of stress could be dangerously high or that they may have anxiety or depression should speak with a healthcare provider.
Meanwhile, doctors can use epinephrine to treat many life threatening conditions, including:
- anaphylaxis, a severe allergic reaction
- asthma attacks
- cardiac arrest
- severe infections
Epinephrine’s ability to constrict blood vessels can decrease swelling that results from allergic reactions and asthma attacks. In addition, epinephrine helps the heart contract again if it has stopped during cardiac arrest.
Gamma-aminobutyric acid (GABA) is a mood regulator. It has an inhibitory action, which stops neurons from becoming overexcited. This is why low levels of GABA can cause anxiety, irritability, and restlessness.
Benzodiazepines, or “benzos,” are drugs that can treat anxiety. They work by increasing the action of GABA. This has a calming effect that can treat anxiety attacks.
GABA is available in supplement form, but it is unclear whether these supplements help boost GABA levels in the body, according to some research.
Exposure to sunlight may increase serotonin levels.
Serotonin is an inhibitory neurotransmitter. It helps regulate mood, appetite, blood clotting, sleep, and the body’s circadian rhythm.
Serotonin plays a role in depression and anxiety. Selective serotonin reuptake inhibitors, or SSRIs, can relieve depression by increasing serotonin levels in the brain.
Seasonal affective disorder (SAD) causes symptoms of depression in the fall and winter, when daylight is less abundant. Research indicates that SAD is linked to lower levels of serotonin.
Serotonin-norepinephrine reuptake inhibitors (SNRIs) increase serotonin and norepinephrine, which is another neurotransmitter. People take SNRIs to relieve symptoms of depression, anxiety, chronic pain, and fibromyalgia.
Some evidence indicates that people can increase serotonin naturally through:
- being exposed to bright light, especially sunlight
- vigorous exercise
A precursor to serotonin, called 5-hydroxytryptophan (5-HTP), is available as a supplement. However, some research has found that 5-HTP is not a safe or effective treatment for depression and can possibly make the condition worse.
Neurotransmitters play a role in nearly every function in the human body.
A balance of neurotransmitters is necessary to prevent certain health conditions, such as depression, anxiety, Alzheimer’s disease, and Parkinson’s disease.
There is no proven way to ensure that neurotransmitters are balanced and working correctly. However, having a healthful lifestyle that includes regular exercise and stress management can help, in some cases.
Before trying a supplement, ask a healthcare provider. Supplements can interact with medications and may be otherwise unsafe, especially for people with certain health conditions.
Health conditions that result from an imbalance of neurotransmitters often require treatment from a professional. See a doctor regularly to discuss physical and mental health concerns.