Neurotransmitters are chemical messengers in the body. Their function is to transmit signals from nerve cells to target cells. These signals help regulate bodily functions ranging from heart rate to appetite.

Neurotransmitters are part of the nervous system. They play a crucial role in human development and many bodily functions.

This article explains what neurotransmitters are, what they do, and some different types.

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The nervous system controls the body’s organs and plays a role in nearly all bodily 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, also known as the body’s chemical messengers. These chemicals 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, it triggers an action in the target cells.

After neurotransmitters deliver their messages, the body breaks them down or recycles them.

The brain needs neurotransmitters to regulate many necessary functions, including:

Neurotransmitters also play a role in early human development.

Experts have identified over 100 neurotransmitters to date and are still discovering more.

Neurotransmitters have different types of actions:

  • 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 several functions depending on the type of receptor they connect to.

The following sections describe some of the best-known neurotransmitters.

Acetylcholine is an excitatory neurotransmitter with a wide range of roles.

For example, it:

  • triggers muscle contractions
  • stimulates saliva and sweat production
  • controls the heartbeat

It also plays a role in memory, motivation, and attention.

Low levels of acetylcholine link with issues relating to memory and thinking, such as Alzheimer’s disease.

Some Alzheimer’s disease medications help slow the breakdown of acetylcholine in the body. This can help manage some symptoms, such as memory loss.

Having high levels of acetylcholine can cause too much muscle contraction.

This can lead to:

  • increased saliva and tears
  • muscle weakness and paralysis
  • diarrhea
  • blurry vision

The nutrient choline, present in many foods, is a building block of acetylcholine. People need choline in their diet to produce enough acetylcholine. However, it is not clear whether consuming more choline can help boost levels of this neurotransmitter.

Choline is present in beef liver, eggs, soybeans, and potatoes. Choline supplements are also available. However, there is not enough evidence to show they help with any health condition. However, taking too much can have adverse effects, such as a fishy body odor, sweating, low blood pressure, and liver damage.

Dopamine is important for:

Many people know dopamine as a pleasure or reward neurotransmitter. The brain releases dopamine during pleasurable activities.

Researchers believe there is a link between dopamine deficiency and Parkinson’s disease.

Drugs that regulate dopamine levels may help treat features of Parkinson’s disease as well as depression, addiction, anxiety, bipolar disorder, and other conditions.

The body needs certain amino acids to produce dopamine. Amino acids are present in protein-rich foods, such as meat, fish, and eggs. However, there is no evidence that suggests eating these foods makes a difference in dopamine levels.

While there are no dopamine supplements, exercise may help boost levels naturally. Research has shown that regular exercise improves dopamine signaling in people with early stage Parkinson’s disease.

Endorphins inhibit pain signals and create a feeling of pleasure. They have links to laughter, love, sex, and appetizing food.

Many people feel better after exercising. One reason for this may be that exercise boosts endorphin levels. Laughter may also cause a release of endorphins, according to research published in The Journal of Neuroscience.

Endorphins may also help manage pain. A review of research published in Current Pain and Headache Reports says that aerobic exercise can help prevent migraine frequency, duration, and intensity.

The Arthritis Foundation recommends exercise for people with fibromyalgia to reduce pain and boost mood.

Epinephrine (also known as adrenaline) plays a role in the body’s “fight-or-flight” response. It is both a hormone and a neurotransmitter.

When a person experiences stress or fear, their body releases epinephrine. This increases heart rate and breathing and gives the muscles a jolt of energy. It also helps the brain make quick decisions.

However, chronic stress can cause the body to release too much epinephrine. Over time, stress can lead to health problems such as decreased immunity, high blood pressure, diabetes, and heart disease, according to the National Institute of Mental Health.

Doctors can use epinephrine to treat some life threatening conditions, including:

Epinephrine’s ability to constrict blood vessels can decrease swelling that results from allergic reactions and asthma attacks. In addition, it can help the heart contract again if it has stopped during cardiac arrest.

Gamma-aminobutyric acid (GABA) is the central nervous system’s main inhibitor. It is a mood regulator, and experts have linked low levels of it with anxiety, depression, and schizophrenia.

Benzodiazepines, or “benzos,” are drugs that can treat anxiety. They work by increasing the action of GABA. This has a calming effect that can help treat anxiety attacks.

GABA comes in supplement form. However, research published in Frontiers in Psychology has not confirmed whether these supplements can boost GABA levels in the body.

Serotonin is an inhibitory neurotransmitter. It helps regulate mood, behavior, sleep, and memory.

Seasonal affective disorder (SAD) causes symptoms of depression in the fall and winter when daylight is less abundant. Research published in Brain suggests there may be a link between SAD and low serotonin levels.

Doctors prescribe selective serotonin reuptake inhibitors (SSRIs) to treat a range of conditions, including:

SSRIs boost serotonin levels by stopping the body from reabsorbing serotonin, leaving more serotonin to pass messages between nerve cells.

Serotonin-norepinephrine reuptake inhibitors (SNRIs) increase serotonin and norepinephrine, another neurotransmitter. SNRIs can help relieve symptoms of depression, anxiety, chronic pain, and fibromyalgia.

Evidence published in the journal Cell indicates that exposure to sunlight may help increase serotonin levels, although people should take care to avoid sunburn.

A precursor to serotonin, 5-hydroxytryptophan, is available as a supplement. Some studies suggest this ingredient may help treat depression and other conditions. However, more research is needed.

People should speak with a doctor before taking this supplement, or any supplement, to treat depression.

Learn more about SSRIs and other antidepressants.

Neurotransmitters contribute to nearly every function in the human body. An appropriate balance of neurotransmitters can help prevent certain health conditions, such as depression, anxiety, and Parkinson’s disease.

There is no proven way to ensure that neurotransmitters are balanced and working correctly. However, consuming a nutritious diet, getting regular exercise, and stress management can help in some cases.

Some people try supplements to boost certain neurotransmitters. In most cases, there is not enough evidence to show they work. Anyone considering using supplements should check first with a doctor. Supplements can interact with medications and may not be safe to use with some health conditions.

Anyone experiencing symptoms that may be due to an imbalance should seek medical advice.