Mental Health: The Neurotransmitter Edition. Part I

(www.DougCookRD.com)

Brain and mental health concerns affect a huge number of people. But, where does it all come from? Does it start, or continue, because of the way the brain and nervous system is working?

 

Some of it is genetic, passed down from our families. Some of it is triggered by stress and/or traumatic life events. Many times it seems to be related to “brain chemicals” called neurotransmitters. And, most likely, it’s a complex combination of many of these, plus other factors!

 

Today we’re talking neurotransmitters and their roles in mental health for stress and mood. Plus, I’ll let you in on what doesn’t work, as well as one major thing you can do to help to boost your brain health, mental health (and neurotransmitters)!

 

Neuro-what? (Neurotransmitters)

 

Our nerves are one of the main communication systems in our body. The whole nervous system including our brain, spinal cord, nerve cells and a few other key cells is sometimes called the “master communication system of the body.”

 

Ever wonder how these cells communicate, and what this may have to do with mental health and brain health?

 

This is where “neurotransmitters” come in. They are “brain chemicals” made from protein. Neurotransmitters do exactly that – they transmit information between nerve cells. They help our neurons “talk” to each other, BUT neurotransmitters are also produced in the gut/digestive tract and where ever they are made, they impact the brain and, in turn, influence our moods.

 

FUN FACT: Nerve cells are called “neurons.” Our nervous system has other types of cells as well.

 

We have billions of neurons in our body. About 90 billion of them are in our brains, and there are billions more in our spinal cords and the rest of our bodies [including the digestive tract – hence the expression “second brain”]. Neurons relay messages from our brain and spinal cord (central nervous system) to our big toes, everywhere else in our bodies, and all the way back.

 

In fact,

“All sensations, movements, thoughts, memories, and feelings are the result of signals that pass through neurons.” (NIH)

 

This is why the research into neurotransmitters is so very important when it comes to brain and mental health!

 

How Neurotransmitters Work

 

Neurons use both electrical and chemical signals to transmit messages. A neuron is a nerve cell with a long tail-like end called a “dendrite.” When it gets a message, it sends the signal from one end of the tail all the way down to the other end of the cell via electricity. But, it can’t send it’s electrical signal through to its neighbouring neuron. To send that message over, it communicates with its neighbouring neuron by neurotransmitters.

 

Here’s how it works.

 

NOTE: Think of the game “hot potato” where people are in a line or a circle beside each other. The first person gets the “hot potato” and needs to pass it to their neighbour. This has to continue as quickly as possible until the potato gets to the right place.

 

In real life, a neuron gets a signal, say you touch something hot. Let’s consider this “hot” signal the “hot potato.” That neuron in your finger gets the message and needs to quickly send it through the communication network all the way to the spinal cord or brain.

 

It first sends the signal as an electrical signal through its “tail” all the way to its other end. Think of this as the first person holding the potato and turning toward their neighbour while still holding the potato. In your neurons this is done electrically, so while the potato is in someone’s hands it’s like the electrical signal going from one side to the other.

 

But that one neuron doesn’t reach all the way where the signal needs to go – it needs to get to your spinal cord or brain. So, it has to relay that signal to its neighbouring neuron. Here’s where it passes the “potato” to the neighbour. But the problem is that it can’t pass the electricity. So, it has to change that signal into a chemical to get to the neighbouring cell. This is where neurotransmitters come in.

 

This neurotransmitter goes through the tiny space between the two cells called a “synapse.” When that neurotransmitter reaches that neighbouring neuron it attaches to a “receptor.” That receptor is the neighbour’s hands that catch that “hot potato.” When that neurotransmitter gets to that second cell, it then changes the chemical signal back into an electrical one.

 

This electrical-chemical communication happens really quickly and continues until the message gets to where it needs to go. From your fingertip up to your spinal cord or brain where a super-quick decision is made. Then another signal goes back down to your finger to move the muscles to quickly pull it away from the pain.

 

This is how our nervous system is the master communication system of the body! It’s how our brain knows if it should be awake (because of the light your eyes see), whether you’re too hot (and need to sweat to cool off), or whether you’re in danger (and need to “fight or flee”).

 

Key Neurotransmitters

 

There are many different neurotransmitters. Let’s look at three key ones, and what we know so far about their roles in stress and moods.

 

#1 – Serotonin (“happy”)

 

Serotonin, also known as 5-hydroxytryptamine (5-HT), has many roles in the nervous system. It’s involved with maintaining our body temperature and is transformed into melatonin to help us get sleepy when the light starts to dim. It’s also important for our memory, our stress response, as well as processing our emotions.

 

Serotonin is made from the amino acid (one of the building blocks of protein) tryptophan. Because of its role in mental health, many medications for depression target the serotonin that is produced in the brain.

 

Some serotonin is made in the brain, but most of it is actually made in the gut. One of serotonin’s roles in the gut is to help our gut keep food moving through it (“gastric motility”). Researchers are looking into the roles of the serotonin produced in the gut – at this point it’s unclear whether the serotonin made in the gut travels to or affects the brain.

 

#2 – Norepinephrine (NE) (“alertness” and “stress”)

 

Norepinephrine (NE) is a neurotransmitter released in brain and is involved in the stress response. If you’ve heard of “adrenaline,” and the adrenaline rush of being on a rollercoaster or bungee jumping, you’ve heard of epinephrine. Epinephrine is another name for adrenaline. It’s a huge part of our “fight or flight” reaction.

 

The part of our nervous system that is activated when we’re stressed and when we feel anxious results in a rapid release of norepinephrine in the brain.

 

Norepinephrine is made from the third neurotransmitter we’re talking about, dopamine.

 

#3 – Dopamine (DA) (“motivation”, “focus”, “reward” & “behaviour”)

 

Dopamine (DA) is the “motivation” neurotransmitter – it helps us to seek reward. Dopamine helps to turn our enjoyment of a reward into the desire to go out and get that reward. In this way it’s thought that dopamine helps to shape behaviour. Some medications used to treat behavioural disorders work by changing how dopamine acts in the brain.

 

This “motivation” role of dopamine is also involved in our moods. For example, when dopamine levels are low, we can experience “anhedonia” which is when we lose our motivation to seek out reward.

 

Dopamine has other roles in brain and nervous system communication too. It’s important for working memory and mental flexibility. It also helps to control our movement. For example, when certain parts of the brain don’t have enough dopamine, it can result in the muscular rigidity of Parkinson’s disease.

 

Dopamine is made from the amino acid called “tyrosine.”

 

Neurotransmitters and Stress

 

Stress is anything that challenges our body’s ability to maintain optimal health and have all of our systems balanced. This goes for mental health (psychological stress) as well as physical stress (i.e. exercise and/or being cold).

 

Our natural physical and mental reactions to stress are for our own survival. Psychological stress can trigger our brain to react to danger. And our “fight or flight” response happens whether we’re scared because we’re on a roller coaster, whether we almost got in a car accident, or whether we’re overworked and worried about our jobs. These are all examples of psychological stress, and they all cause the same response in the brain and the body.

 

Neurotransmitters and Mental Health

 

Depression and anxiety are some of the most common mental health concerns in the world. Many people experience both, and women are more likely than men to be diagnosed. In the next 13 years, depression may become the leading cause of disability in the United States.

 

Depression involves a persistent feeling of sadness and loss of interest, empty, or irritable mood that can significantly affect someone’s ability to function. Sometimes there are sleep issues, lack of energy, and effects on appetite, and anhedonia (a lack of motivation to seek out things that used to interest us or make us happy). Depression affects how someone feels, thinks, and behaves. The symptoms might differ from person to person.

 

The causes of depression seem to be very complex, with many possible reasons that are unique to each individual. Reasons like genetics, hormones, stress and emotional loss may all contribute to the risk of depression.

 

A lot of research has looked at the structure and function of the brain to understand how it controls mood and emotions. One of the most popular ideas that started in the 1950s relates to neurotransmitters. The idea (or “hypothesis”) is that a deficiency in the “happy” neurotransmitter serotonin (5-HT) and the “stress” neurotransmitter norepinephrine (NE) is one reason for depression. Over the years, a possible role of dopamine has been added to this concept of depression.

 

When it comes to serotonin, it’s thought that not having enough serotonin in the right spots is one of the contributors. Because of its role in mood, many medications for depression target this neurotransmitter. Some newer medications also target norepinephrine and/or dopamine. It’s known that some people benefit from these medications, but others do not get better.

 

NOTE: If you think you may have depression, anxiety, or any brain or mental health concern, please see your licensed healthcare professional.

 

In Part II, I’ll talk about how different foods, supplements & exercise affect neurtransmitters, brain and mental health! Stay tuned!

 

 

References:

 

Belujon, P., & Grace, A. A. (2015). Regulation of dopamine system responsivity and its adaptive and pathological response to stress. Proceedings of the Royal Society B: Biological Sciences, 282(1805), 20142516. http://doi.org/10.1098/rspb.2014.2516

 

Belujon, P., & Grace, A.A. (2017). Dopamine System Dysregulation in Major Depressive Disorders. International Journal of Neuropsychopharmacology, 20(12), 1036–1046. http://doi.org/10.1093/ijnp/pyx056

 

Chand, S.P. and Whitten, R.A. (2018) Depression. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK430847/

 

Examine.com. Supplements: 5-HTP. Accessed May 7, 2018.  https://examine.com/supplements/5-htp/

 

Mayo Clinic. Depression (Major Depressive Disorder). Accessed May 2, 2018,  https://www.mayoclinic.org/diseases-conditions/depression/symptoms-causes/syc-20356007?p=1

 

National Institutes of Health. Eunice Kennedy Shriver National Institute of Child Health and Human Development. What are the parts of the nervous system? Accessed May 2, 2018.  https://www.nichd.nih.gov/health/topics/neuro/conditioninfo/parts

 

National Institutes of Health. U.S. National Library of Medicine. MedLine Plus. Nerve conduction. Accessed May 2, 2018:  https://medlineplus.gov/ency/anatomyvideos/000089.htm

 

 

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