Neurotransmitters: 5 Crazy Chemicals that Control Almost Everything

You’ve probably heard of how dopamine plays a role in feelings of pleasure, or how serotonin levels influence depression. But, neurotransmitters do so much more than make us feel happy or sad. Not only do they influence our mood, but they also influence how our hearts beat, how our lungs breathe, and how our stomachs digest the food we eat. Here’s a crash course on everything you need to know about neurotransmitters.

Understanding the different types of neurotransmitters
Understanding the different types of neurotransmitters

Test Your Knowledge

How much do you know about neurotransmitters? Take the quiz to find out!

[rapid_quiz question=”Which neurotransmitter has 5 different receptors for it?” answer=”Dopamine” options=”Acetylcholine|Dopamine|Serotonin|Glutamate” notes=”Dopamine actually has 5 different receptors, creatively named D1, D2, D3, D4 and D5. Different receptors are located in different parts of the brain. This allows the neurotransmitter to be used in many different ways. For example, when dopamine interacts with the D1 receptor in the limbic system, it plays a role in behavioral responses.”]

[rapid_quiz question=”Which neurotransmitter is also called 5-hydroxytryptamine, or 5-HT for short?” answer=”Serotonin” options=”Dopamine|GABA|Epinephrine|Serotonin” notes=”Serotonin is also known as 5-hydroxytryptamine, or 5-HT. This is because the neurotransmitter is made from the amino acid tryptophan. Tryptophan is commonly found in foods such as grains, meat, and dairy products, so having a deficiency in tryptophan can lead to decreased levels of serotonin.”]

[rapid_quiz question=”Which of the following neurotransmitters are inhibitory?” answer=”GABA” options=”GABA|Acetylcholine|Epinephrine|Norepinephrine” notes=”GABA is an inhibitory neurotransmitter, meaning that it tells the next neuron not to fire an action potential. An excitatory neurotransmitter, such as epinephrine or norepinephrine, tell the next neuron to fire an action potential, and thus causing the release of even more neurotransmitters.”]

[rapid_quiz question=”The area in which neurotransmitters are released from one cell to communicate with the other is called the _____” answer=”synapse” options=”dendrites|axon|synapse|myelin sheath” notes=”The synapse is where all of the magic happens. The neurotransmitters are released from the terminals of one cell to interact with receptors on the dendrites of the other cell. “]

[rapid_quiz question=”When there is a neurochemical imbalance causing an issue or illness, scientists can develop drugs that help to balance it. What is a major consideration when developing drugs that influence brain chemistry?” answer=”the blood-brain barrier” options=”the blood-brain barrier|nature of the neurotransmitter (inhibitory, excitatory)|type of neurotransmitter|location of the neurotransmitter in the brain” notes=”While all of these are important considerations, the blood-brain barrier is the biggest obstacle scientists have to face when making drugs targeting the brain. The blood-brain barrier is a highly selective barrier that only allows certain nutrients and chemicals to pass through. This allows for a constant environment in the brain, and protects the brain from any potentially dangerous substances.”]

What are Neurotransmitters? – How They Work:

Before we can learn about the different types of neurotransmitters, we need to understand what neurotransmitters are and how they work.

Neurotransmitters are chemicals that are released from nerve cells to other target cells to communicate information.

Neurons can communicate using both electrical and chemical methods. Tiny packages called vesicles are hidden within the synaptic terminal (get to know your brain) of each neuron. These vesicles contain the neurotransmitters that are released when stimulated by an electrical impulse called an action potential. Once these vesicles are given a signal to open, they travel to the cell’s membrane and release the neurotransmitters into the synapse. The synapse is a gap between the dendrites of one neuron and the axon terminal of another neuron.

Neurotransmitters interact with receptors on the dendrites of the other neuron, much like how a lock and key work. The neurotransmitters have specific shapes that fit into a receptor that can accommodate that shape. Once the neurotransmitter and the receptor are connected, the neurotransmitter sends information to the next neuron to either fire an action potential, or to inhibit firing. If the neuron gets the signal to fire, then the whole process starts over again along the chain of neurons.

5 Main Types of Neurotransmitters

It would be very long and complicated to tell you about every neurotransmitter in the brain and what it is responsible for. So instead, let’s take a look at the 5 major types of neurotransmitters and what they do.

Types of neurotransmitters: Dopamine

Dopamine plays many different roles in the brain, depending on the location. In the frontal cortex, dopamine acts as a traffic officer by controlling the flow of information to other areas of the brain. It also plays a role in attention, problem-solving, and memory. And you’ve probably heard how dopamine plays a role in things that give us pleasure. So if you were to eat a piece of chocolate, dopamine would be released in some areas of the brain, allowing you to feel enjoyment, motivating you to eat more chocolate.

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Types of neurotransmitters: Serotonin

Serotonin is known as an inhibitory neurotransmitter, meaning that it doesn’t give the next neuron the signal to fire. Serotonin is involved with mood, as well as your sleep cycle (click here to find out how to become a morning person!), pain control, and digestion. In fact, the majority of serotonin in the body can be found in the gastrointestinal tract, and only about 10% is located in the brain. Aside from aiding in digestion, serotonin can also help with forming blood clots and increasing sex drive.

Types of neurotransmitters: Acetylcholine

Acetylcholine (ACh) plays a major role in the formation of memories, verbal and logical reasoning, and concentration. ACh has also shown to help with synaptogenesis or the production of new and healthy synapses throughout the brain. Acetylcholine comes from the chemical known as choline, which can be found in foods such as eggs, seafood, and nuts.

Acetylcholine also plays a significant role in movement. A nerve cell can release ACh into a neuromuscular junction, which is a synaptic connection between a muscle fiber and a nerve cell. When ACh is released, it causes a series of mechanical and chemical reactions that result in the contraction of muscles. When there is a lack of ACh in the neuromuscular junction, the reactions stop, and the muscle relaxes.

Types of neurotransmitters: GABA

GABA is also an inhibitory neurotransmitter that helps to balance any neurons that might be over-firing. This inhibitory ability becomes especially helpful when it comes to anxiety or fear because the release of GABA helps to calm you down. In fact, caffeine actually works to inhibit GABA from being released, so that there is more stimulation in the brain.

GABA also plays a role in vision and motor control. Some drugs work to increase the levels of GABA in the brain. This increase helps with epilepsy and helps to treat the trembling found in patients with Huntington’s disease.

Types of neurotransmitters: Noradrenaline (norepinephrine)

These might sound like two big and confusing words because you’ve probably heard about adrenaline (epinephrine) before. Before we go any further, let’s define these terms.

Another name for adrenaline is epinephrine. Epinephrine is a hormone that is secreted by the adrenal gland, which is a gland that rests on top of the kidneys. Hormones are molecules that are released into the bloodstream.

Noradrenaline is also known as norepinephrine. Norepinephrine is a neurotransmitter, meaning that it is used for interactions between neurons.

Noradrenaline is an excitatory neurotransmitter that helps to activate the sympathetic nervous system, which is responsible for your “fight or flight” response to a stressor. Norepinephrine also plays a role in attention, emotion, sleeping and dreaming, and learning. When it is released into the bloodstreams, it helps to increase heart rate, release glucose energy stores, and increase blood flow to the muscles.

When Neurotransmitters Go Wrong: Chemical Imbalances in the Brain

When the neurotransmitters are balanced, it helps us to lead healthy and balanced lives. But sometimes the environment or our genes can trigger imbalances in these essential chemicals, causing illnesses such as depression, Parkinson’s disease, and schizophrenia to arise (see more about brain gym exercises for these diseases).

Chemical imbalances in the brain: Depression

There are many known causes of depression, with one of them being the amount of serotonin in the brain. Studies have shown that decreases in the production of serotonin in the brain can lead to feelings of depression. In some cases, low serotonin levels can lead to suicidal thoughts. Other studies link lower levels of norepinephrine to depression. These studies suggest that the low levels of serotonin are actually suppressing the levels of norepinephrine, causing a depressed mood. (Are antidepressants for you?)

Chemical imbalances in the brain: Parkinson’s Disease

Parkinson’s Disease (PD) is a neurodegenerative disorder that affects the neurons responsible for movement in the body. Since dopamine is responsible for transmitting information about movement, the death of these neurons can cause symptoms such as tremors, stiffness, or balance issues. The body tries to compensate for the lack of dopamine by releasing more glutamate, which is a neurotransmitter that has a role in learning and memory. However, glutamate is an excitatory neurotransmitter, and having too much glutamate can lead to the overexcitement and eventual death of neurons.

Treatments for Parkinson’s Disease include L-Dopa, which is a precursor to dopamine that can cross the blood-brain barrier and relieve movement problems.

Chemical imbalances in the brain: Schizophrenia

Schizophrenia is a disabling disorder that impacts how a person thinks, feels, and acts. Research shows that some imbalances in dopamine might play a role. The “dopamine hypothesis” states that having too much dopamine in the brain can cause schizophrenia. This idea led to antipsychotic medications that aim to lower the amount of dopamine released in the brain and reduce the symptoms of schizophrenia.

But there are other small changes in the brain that may contribute to schizophrenia. For example, the ventricles, or areas of the brain filled with cerebrospinal fluid (CSF), are larger in patients with schizophrenia.  However, these differences are not significant enough to generalize for all people with schizophrenia. Read here for more information on how to reduce the symptoms of schizophrenia.

Depression can be linked to neurotransmitter imbalances
Depression can be linked to neurotransmitter imbalances

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