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Neurotransmitters: What To Know

Medically Reviewed by Poonam Sachdev on September 01, 2022

Your body functions using chemical messages that are directed throughout your system with specific targets. These chemical messages are carried by neurotransmitters, which act as a messenger directing messages from point A to point B. These messages are vital for your daily functions, including the movement of your limbs, the ability to feel sensations, and your response to information from internal body parts and your environment. In addition, the messages passed along by neurotransmitters help to keep your heart beating. 

What Are Neurotransmitters?

Neurotransmitters are vital to your body’s ability to function. Their role is to carry messages from one nerve cell to another cell, which can be another nerve cell, a muscle cell, or a gland cell. 

Your nervous system houses a wide network of nerves that work to send and receive messages throughout your body. As a result, your nervous system is responsible for controlling many of your bodily functions involving your mind, muscles, and various organs. Essentially, your nerves play a significant role in everything you feel, think, and do. 

Where Are Neurotransmitters Located?

Neurotransmitters are stored inside synaptic vesicles, which are thin-walled sacs. These sacs contain thousands of neurotransmitter molecules and are located inside a part of the neuron known as the axon terminal. 

Types of Neurotransmitters

There are two main types of neurotransmitters: small-molecule transmitters and neuropeptides. Within these two types of neurotransmitters are smaller types of neurotransmitters. 

Many of these neurotransmitters are complicated and multi-faceted, meaning they have many roles and responsibilities. Some work well together while others work against each other. 

There are many different types of neurotransmitters, with more than 60 currently known. Here are some of the most common neurotransmitters researched and discussed by neuroscientists: 

  • Acetylcholine: Acetylcholine (Ach) was the first neurotransmitter discovered. It is a small-molecule neurotransmitter that works with muscles to help them move. To do so, acetylcholine translates our impulse to move into actual action.
  • Dopamine:Dopamine (DA) is a pleasure chemical that is released during pleasurable activities such as eating and sexual intercourse. In addition, it plays a significant role in motivation, working memory, decision-making, and other functions. Due to its diverse effects on human behavior, dopamine is one of the most heavily researched neurochemicals.
  • Glutamate: Glutamate (GLU) is a neurotransmitter with many bad associations. For example, too much glutamate in the body can result in the death of neurons. This occurs during a stroke, brain injury, or diseases such as Lou Gehrig’s disease. However, glutamate has some good aspects, too, including aiding in memory formation.
  • Serotonin:Serotonin (5HT) is also known as a calming chemical due to its role in mood regulation. When insufficient serotonin is present in the body, depression and other neuropsychiatric disorders can occur. Serotonin also affects sleep, appetite, memory, and even decision-making.
  • Norepinephrine: While norepinephrine is a neurotransmitter, it is also a hormone. It regulates mood, stimulation, vigilance, stress, and memory and has been linked to post-traumatic stress disorder and Parkinson’s disease.
  • Gamma-Aminobutyric Acid: Gamma-aminobutyric acid (GABA) is responsible for inhibiting neural signaling. In cases where it inhibits cells too much, seizures and other medical conditions can occur. GABA also plays a significant role in brain development and has been nicknamed the learning chemical.

Additional Neurotransmitters

Oxytocin and vasopressin are neurochemicals that are also recognized as neurotransmitters. They are associated with monogamous behaviors and drug addiction. 

Certain other hormones are also classified as neurotransmitters. These hormones, which include estrogen and testosterone, often influence synaptic activity. 

In addition to these neurotransmitters, there are other types that are linked to the brain’s response to stressful situations and environments. These neurotransmitters include galanin, dynorphin, neuropeptide, and more. 

Another type of neurotransmitter known as enkephalin releases alongside glutamate, which helps signal the desire to eat or process rewards. 

What Do Neurotransmitters Do?

Neurotransmitters play a significant role in improving and balancing brain signals and maintaining a functioning brain. Neurotransmitters function to promote automatic responses like breathing and keeping the heart beating. In addition, they also provide psychological functions relating to mood regulation, pleasure, and learning. 

Different neurotransmitters play one of three roles:  

  • Excitatory: As their name implies, excitatory neurotransmitters are responsible for exciting the neuron and causing it to pass a message to the next cell.
  • Inhibitory: Inhibitory neurotransmitters are responsible for blocking and preventing chemical messages from being passed on further.  
  • Modulatory: Modulatory neurotransmitters are responsible for influencing chemical messengers. For example, they can adjust how cells communicate and can affect several neurons at the same time.

Once neurotransmitters have delivered their message, they are either diffused, reabsorbed and reused, or broken down by enzymes. 

Faulty Neurotransmitters

Neurotransmitters don’t always work as they should, and there are several reasons why a neurotransmitter may be faulty. Some of these problems include: 

  • Too many neurotransmitters are produced and/or released.
  • Two few neurotransmitters are being produced and/or released. 
  • The receiver cell’s receptor is not working properly. 
  • Inflammation and damage of the synaptic cleft, the area between the initial nerve cell and the target, has occurred, resulting in the cell receptors not receiving all signals. 
  • Reabsorption of neurotransmitters happens too quickly. 
  • The number of neurotransmitters is limited by enzymes, resulting in fewer neurotransmitters reaching their target cell. 

In addition, diseases and medications can affect neurotransmitters and cause them to become defective. 

As a result of neurotransmitters not working properly, certain diseases can occur. For example, when there is not enough acetylcholine present, memory loss can occur. This often affects Alzheimer’s patients. Patients with autism spectrum disorder, meanwhile, often produce too much serotonin. In other cases, seizures can result when an increase or reduction in the activity of GABA occurs. 

Show Sources

SOURCES: 

Cleveland Clinic: “Neurotransmitters.”

Dana Foundation: “Neurotransmitters.”

SimplyPsychology: “Neurotransmitters: Types, Function and Examples.”

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