Just like there are many different people for different jobs, there are many different types of neurotransmitters, each designed to carry specific messages to start or stop different actions. While the exact number of these different types of neurotransmitters isn’t known, recent research suggests that there may be over 100 different types of neurotransmitters in the body.
What do neurotransmitters do?
While neurotransmitters can help your body do an enormous number of things, from telling your pupils to widen or your arm to move, their most basic functioning can be categorized in three ways. Neurotransmitters can be:
- Excitatory neurotransmitters: These chemical messengers get things started; they tell a target cell to take a type of action.
- Inhibitory neurotransmitters: These chemical messengers stop or prevent things from happening; they decrease the likelihood of a target cell taking a certain action.
- Modulatory neurotransmitters: These chemical messengers regulate groups of neurons; they can send messages to many neurons at the same time and can communicate with other neurotransmitters.
Excitatory neurotransmitters encourage the creation of an electrical signal inside the receiving neuron, whereas inhibitory transmitters will prevent it. Modulatory neurotransmitters, on the other hand, work a little differently. Like little ‘megaphone messengers’, they can communicate to many neurons at the same time and operate slower than excitatory and inhibitory chemical messengers.
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How do neurotransmitters work?
Neurotransmitters help neurons send messages to each other, and in turn, help send messages to all parts of the mind and body. But why are they needed and how do they work?
While messages may travel along a ‘chain’ of neurons, unlike an actual chain each neuron isn’t physically connected to its neighbor. These gaps between neurons are called synapses. So, for the message to travel along each separated link in the chain, a chemical messenger (the neurotransmitter) needs to travel between them. This process is called neurotransmission.
Generally, a neurotransmitter will be released from one end of a typical neuron (the axon terminal) after an electrical signal (action potential) reaches the neuronal junction where messages can leave the neuron and travel to another (the synapse).
When the electrical signal reaches the synapse, it starts a chain-reactions that release neurotransmitters towards the neighboring neuron, whereupon it attaches to a specific receptor site. The neuron can then excite or inhibit changes in the cell. Different receptors can only bind to specific neurotransmitters that are responsible for starting or stopping an action occurring in your body.
Problems in this process can occur when there is an overproduction of neurotransmitters and a lack of receptor sites on the receiving neuron. Often, when neurotransmitters are released into the synapse, too many are released, and the axon (the middle length of a nerve cell that sends the neurotransmitters) has to reuptake (reabsorb) the chemical messengers to avoid flooding the synapse.
Many drugs act on the process of neurotransmissions, such as selective serotonin reuptake inhibitors (SSRIs) that are sometimes used to treat anxiety and depression. SSRIs are a class of drugs that stop the reabsorption of the neurotransmitter serotonin from the neuron it came from to help ensure that more serotonin can get into the brain and reach the receptors that need it.
Some types of neurotransmitters that are working in your body right now
Think you don’t know any of the 100 or so neurotransmitters? You might know more than you think. The names and effects of some common neurotransmitters are well known, such as adrenaline and endorphins. Here are eight common neurotransmitters that are key to your body’s functioning.
This was one of the first neurotransmitters to be discovered. Acetylcholine plays a major role in both the central nervous system (also known as the CNS, which consists of the brain and the spinal cord) and the peripheral nervous system (also known as the PNS: the system of nerves outside the brain and the spinal cord). Acetylcholine, amongst many other things, helps the CNS maintain cognitive function (including thought and learning) and the PNS control the functioning of muscles and organs.
This neurotransmitter is the main excitatory transmitter in the brain and the CNS—it makes things happen! Glutamate plays a key role in some of your brain’s most basic functions, such as memory and learning (synaptic plasticity), though it is understood to be involved in almost every main excitatory brain function.
Epinephrine, also known as adrenaline, is one of the more well-known neurotransmitters. It’s a key force behind the body’s fight-or-flight response (an ‘adrenaline rush’) and powers the body with a quick burst of energy so that it can escape or confront potential dangers. Epinephrine can increase blood sugar levels, heart rate, contractility (how the heart muscles contract), and improves breathing.
Noradrenaline (or norepinephrine)
This is the main neurotransmitter of the sympathetic nervous system. It helps control the activity of organs, blood pressure, heart rate, liver functions, and more. Like epinephrine (adrenaline), noradrenaline also plays a role in the fight-or-flight response. It increases blood sugar levels, heart rate, and contractility. Unlike epinephrine, however, norepinephrine can also increase your blood pressure by narrowing your blood vessels.
Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter that blocks or inhibits brain signals and decreases nervous system activity. GABA is often known as a ‘calming’ neurotransmitter: it can reduce excitability, improve sleep, and even decrease inflammation. While GABA can have a positive effect on stress, anxiety, very high-levels of GABA can be too calming and lead to low energy and foggy concentration. Benzodiazepines (medical relaxants, such as valium, used to calm anxiety) work by increasing the action of GABA.
You might know endorphins as that feel-good chemical that’s experienced after exercise, but did you know they’re also a neurotransmitter? These chemical messengers can inhibit pain signals and trigger a sense of energized well-being. Endorphins are structurally similar to the drug morphine, and as such, they activate opioid receptors in the brain that help reduce pain and discomfort—one of the reasons why they’re considered nature’s pain reliever.
A 2015 study found that while endorphin levels are higher after aerobic exercise, they probably aren’t responsible for exercising 'high'. Their research suggested that another neurotransmitter, called anandamide, might actually be behind the rush of euphoria.
Dopamine is an important neurotransmitter that helps monitor memory and motor control, and plays a major role in supporting normal brain activity. Because the brain releases dopamine during pleasurable activities (dancing, exercising, or even listening to music!), dopamine is often seen as a pleasure or reward neurotransmitter. It encourages you to continue to do activities that make you feel good—which is great for exercise, but not so great for addictive behaviors, like gambling.
Having the right amount of dopamine is crucial to your health and well-being. If dopamine levels are either too low or too high, it can lead to memory problems. Additionally, too high a level may lead to anxiety or hyperactivity, and unbalanced dopamine levels have even been linked to the development of mental illnesses including depression, schizophrenia, and psychosis.
Serotonin is another important neurotransmitter often thought to help us achieve a sense of well-being. It’s involved in many of our bodily functions, such as sleep, appetite, memory, and mood, just to name a few. Serotonin is understood to regulate mood, happiness levels, and anxiety. Low levels of serotonin are linked with various mental health conditions, such as depression or Obsessive Compulsive Disorder (OCD).
Interestingly, serotonin is mostly produced in the gastrointestinal tract—in fact, studies suggest that over 90 percent of the body's serotonin is made in the digestive tract and altered levels of peripheral (outside the brain) serotonin have been linked to conditions such as irritable bowel syndrome (IBS)! This is a great example of how what happens in your brain can affect what happens in your gut, and vise versa, and why treatments like hypnotherapy can treat gut disorders like IBS.
The Wrap Up
Neurotransmitters are types of chemical messengers released by nerve cells (neurons) to stimulate other neurons, muscles, or glandcells. A neurotransmitter can be excitatory (make something happen), inhibitory (stop something from happening), or modulatory (affect multiple neurons simultaneously).
There are over 100 different types of neurotransmitters, each with a different purpose. Some common neurotransmitters include dopamine, endorphins, and adrenaline. Neurotransmitters help us to understand how what happens in our mind can have a huge effect on what we feel in our body, which is great news if you want to try hypnotherapy or meditation to improve your well-being.