By Carissa Weber
Every person speaks a language. Whether it is with their voice, their bodies, or their actions, language is our source of communication. When it comes to our brains, it communicates through tiny chemicals called neurotransmitters.
Our brains utilize several different kinds of neurotransmitters to achieve different tasks. When it comes to mental health, there are several that work (alone, together, or just not at all) to ensure we are enjoying life. This post will cover those neurotransmitters that are hard at work (or just deciding they don’t want to come out and play nicely) to keep us moving forward.
How do these neurotransmitters actually work in the brain? This is a question that gets asked a lot. Although each neurotransmitter does something different, there is a similar process to how they work. Neurotransmitters start in a cell called a neuron. These neurons are located everywhere in the body and are the communication highway in our bodies. With that said, neurons essentially are like a supply chain delivering the goods to the different parts.
When a neuron fires, this ships the neurotransmitter from a certain part of the body and throughout the neuron. As it travels through the neuron, it hits a gap between the neurons. This gap is called the synaptic gap.
This gap is just 20-40 nanometers long (in other words: super tiny) and allows for neurotransmitters to diffuse into the body or continue to travel. If it continues to travel, it will follow through the next neuron and travel down the cell. Once the neurotransmitter is in the synaptic gap, the receiving neuron has the ability to either pass it along the to the next neuron, or allow it to attach to the neuron and complete the reaction. Once the reaction has happened, the neurotransmitter that created the reaction is either broken down by the body or is saved to be recycled and used again. Neat fact: how much neurotransmitter is in the synaptic gap will determine the intensity of the response.
Now that we have a basic understanding of how neurotransmitters work in the brain, this might be the time for us to explore the nine neurotransmitters most commonly involved when discussing mental health. Each neurotransmitter has the ability to cover multiple roles, work together as a team, or work independently for a strong independent response. I think understanding the role of each neurotransmitter will help with the “aha!” lightbulb moment that all therapists love to see.
Since I’m a dork, I am going to go through the neurotransmitters alphabetically. That means we get to start with acetylcholine! It is one of the most prolific neurotransmitters in the body and works on so many different levels. Physically, it is a huge player in muscular contractions (both voluntary and involuntary). As we relate this to mental health, this is the neurotransmitter that will impact your heart rate, make your stomach feel like it is in knots, increases respirations, and puts you on high alert. Acetylcholine is also responsible for helping our brain form and retain memories. This means it works closely with our pals the thalamus and hypothalamus.
Next on the list would be adrenaline. This neurotransmitter is the favorite of that darn amygdala. This darling gem of a neurotransmitter is responsible for what is known as the fight-flight-freeze response. I mentioned it casually in the last blog post, The Brain and Mental Health: The Bigger Break Down, but now is the time and place to go further in depth with it (since this is adrenaline’s job). Lets use the example of, lets say a deer jumping out in front of the car. You’re driving along, minding your own business, and then you see that brown fuzzy thing in the middle of the road. You slam on your breaks and watch the deer bound off, disappearing in the woods. Think about how your body felt. Did your heart rate go up? Were you sweating a bit? Did you seem to recall specific events or memories from seeing that deer? This is because adrenaline flooded our brains (thanks again to the amygdala and the gatekeeper thalamus) to prepare to save our lives.
Adrenaline excites your body and prepares us to either face the stress (like confronting somebody when they ate our last yogurt), running away from a situation (consider the running of the bulls), or freezing up (The classic “deer in the headlights” analogy). As part of that response, the amygdala releases adrenaline to ensure what will keep us safe in the moment. Although it is the amygdala that stimulates releases the adrenaline, it is the thalamus that relays it to the other parts of the brain, especially the hypothalamus, to confirm the brain is indeed in danger. I guess it isn’t that darn amygdala by itself!
Want to learn more about the fight-flight-freeze response in the brain? Stay tuned to to next week’s post!
Dopamine is next on this alphabetical adventure of neurotransmitters. This feel-good neurotransmitter is produced in the hypothalamus. Just like acetylcholine, dopamine serves in a lot of different roles:
- forming and maintaining memories
- maintaining attention
- regulating mood
- how much (or little) we sleep
- learning new skills
- feeling good after we do something we enjoy
That is a lot of roles! Just like I explained in the previous blog post, The Brain and Mental Health: A Bigger Break Down, dopamine travels all throughout the brain like a ping-pong ball to reward our brain for doing things we need for survival. This is why the things we enjoy feel good (like eating our favorite food, jumping in a warm shower, and even after snuggling our favorite pet).
Sometimes, dopamine can be released too much and blow our prefrontal cortex out of the water. In the example of addiction, the substance provides a super dump of dopamine in the amygdala. Once there, the thalamus takes that extra dopamine to the hippocampus, thalamus, and hypothalamus, but leaves the prefrontal cortex in the dark. With the extra dopamine in the synaptic gaps, the brain essentially is rewarding itself for using the substance (especially anything in the amphetamine family). This rewires the brain to need the substance just as much as food, water, shelter, warmth, and the horizontal hokey pokey.
Another fun fact about dopamine is there are consequences if there is too little or too much in your brain. Too little can lead to seizures and Parkinson’s disease. Too much can lead to hallucinations and schizophrenia. Having a healthy balance is key.
“Feelings of gratitude release positive endorphins throughout the body, creating health.”
Adding on to this pleasurable feeling, we can tie in the neurotransmitter, endorphins. Their main role is to assist us in stressful situations to feel less physical pain and really enjoy what we are feeling. Made in the hypothalamus, endorphins are tied to stress reduction and “feeling good.” When you experience a runner’s high, an orgasm, or a really good massage, you can thank the hypothalamus for releasing endorphins to your prefrontal cortex (your prefrontal cortex will thank you!).
Endorphins play a role in addiction as well. Their receptors in the synaptic gap are awfully similar to those of opioid substances. When the opioid binds to those receptors, the endorphins stay in the synaptic gap, leaving you feeling good.
Interesting fact time: endorphins are released as the precursor to the release of dopamine. These two neurotransmitters work very closely together to help us feel pleasure when we experience pain. Low levels of both endorphins and dopamine can be seen as a risk factor for depression (hence why if you struggle with depression you have little pleasure from favorite hobbies, low mood, and have a hard time “feeling” happy about anything). This is why so many people say you should exercise to help boost your mood. That runner’s high will release the endorphins and dopamine your brain is so craving.
Continuing on our alphabet journey, we stop at GABA. This sweet little neurotransmitter is different from the first four mentioned above as it calms the body, not excites it. GABA ( also known as Gamma-aminobutyric acid) is a bit of an odd ball. Rather than getting its start in the brain, it first forms in the pancreas. From there, the hypothalamus collects it to assist in distributing it through the limbic system.
GABA binds to the receptors in the synaptic gap to prevent other neurotransmitters to bind an move on. This inhibits those neurotransmitters (like adrenaline) from binding on and creating chaos in the body. GABA’s effects calm the body down, lessens the physical impact of anxiety, and helps us respond to a stressor appropriately rather than running around like a chicken with our head cut off. When our brain is calm, how do we physically feel? Well, we feel “normal”: heart rate is normal, breathing is normal, muscle tension is normal, it is all normal.
Just like the first couple of neurotransmitters, the body does suffer if there is a shortage of GABA. Not enough GABA can lead to cognitive issues, depression, schizophrenia, seizures, and Huntington’s disease (loss of body mobility). Certain medications can also produce a lot of GABA, including highly addictive medications used to sedate people, calm down anxiety, and relax muscles (not to mention alcohol).
Glutamate is next on the list. Glutamate ranks right up there with acetylcholine as being the most abundant neurotransmitter in our body. Interestingly enough, glutamate is found in 90% of the synaptic gaps in our body (https://www.biohavenpharma.com/science-pipeline/resources/glutamates-role-brain, 2021). This is because glutamate has many different roles not just in the brain, but in the body. As we focus just on the brain, glutamate is responsible for triggering memories. It is the neurons response when our memories are first triggered (both good or bad). When it comes to signaling our body what to do, glutamate is the precursor to the release of GABA to relax us, and to dopamine to excite us.
To add to the cool factor, glutamate has been studied more in the last 10 years and has been found to help form new memories by associating new memories with old ones. Do you ever wonder why a song brings back an old memory? You can thank glutamate for that one!
Just like outlined in my previous post, The Brain and Mental Health: The Bigger Break Down, glutamate jumps all over in the brain. This means no particular part of the brain calls ownership of it. For this reason, it is believed that glutamate is able to help with learning, memory, cognition, sensory information, mood regulation, and a partridge in a pear tree. Glutamate is the epitome of a neurotransmitter that works with all the other neurotransmitters to get a job done. Not only does it get the job done, but since glutamate is also an amino acid, that means it is stored in muscles rather than in the brain. Isn’t glutamate so cool?
Just like discussed with the previous neurotransmitters, there can be negative effects if there is too much, or not enough glutamate in the synaptic gaps. Without glutamate, we lose our ability to focus and can become mentally exhausted. With too much glutamate, symptoms like OCD, anxiety, and schizophrenia can occur. Added to that, excessive glutamate could kill off the neurons surrounding it.
As we continue on this long list of neurotransmitters, noradrenaline is next. Also known as norepinephrine, noradrenaline works closely with adrenaline to increase our blood flow when we are in a stressful situation (like that fight-flight-freeze response we talked about earlier). Add that to the fact that noradrenaline plays a huge role in our circadian rhythm (a.k.a. – the sleep-wake cycle), noradrenaline has a big job ahead of it! Noradrenaline is known for occasionally dumping itself into our synaptic gaps. When it does that, it is the neurotransmitter that signals a panic attack. Guess what you can thank for releasing it? Let me give you a hint, it isn’t that darn amygdala. Actually, it is our adrenal glands. Once the thalamus decides to spread the information of the stress to the amygdala, the amygdala signals the adrenal gland (located directly under the amygdala) to make more!
Now don’t get me wrong, noradrenaline has some positive traits too. For example, if you have ever felt amazing after riding a roller coaster, you can thank noradrenaline. Noradrenaline also is responsible for giving us that extra edge of focus and concentration when we are taking a test. Interesting topic about noradrenaline: it plays a role in ADHD (attention deficit hyperactivity disorder). Believe it or not, ADHD is believed to be related to a shortage of noradrenaline in the brain. Medications used to treat ADHD often increase noradrenaline.
Now if we look on the opposite side of the spectrum, oh let’s say at depression, noradrenaline has a role there, too. Noradrenaline, along with serotonin, are trapped in the synaptic gap. This means it cannot carry on to the next cell and make us feel good. Medications, such as SSRIs and SNRIs, work by allowing the neurons to move noradrenaline and serotonin throughout the body.
Next on the list is oxytocin. Many people think of oxytocin when it comes to pregnant ladies as it is known for inducing labor and helping breast milk drop for babies to eat. Oxytocin is more than that!
Produced in the hypothalamus, oxytocin travels through the amygdala to help calm it down when stress is present. This helps the brain navigate social interactions by doing something rather neat: forming attachments with other humans. Everything from love to jealousy, admiration to hate, oxytocin preps that darn amygdala for experiencing all of those emotions within a human relationship (romantic or not).
Another cool thing oxytocin does is decreasing the production of the stress hormone, cortisol. Why is this important? Cortisol is a hormone released in our guts that tell us “we better get ready for survival.” Stress eating? That is cortisol. Wanting to hide from other humans in general? Lovely cortisol there. When oxytocin bonds inside the synaptic gap, it prevents cortisol from doing so. This helps us see other humans as friends, not an enemy that triggers the fight-flight-freeze response.
The other role oxytocin has is in our sexual reproduction. Yup, where there are erect phallus’ and orgasmic delights, there is oxytocin. Although not completely understood, it is believed that this is to help with the uterus’ movements to help sperm travel to where it needs to be (MacGill, 2017). As oxytocin aids in developing human interaction, this is also the reason why once you “do the deed” with someone, there tends to be a stronger emotional connection to them.
The last neurotransmitter, serotonin (finally!). Before we go into serotonin, I want to thank you guys for hanging in there until the end and taking the time in to investing in learning about your brain. It is hard work to rewire the brain!
Now onto serotonin. Serotonin is the main man for controlling and regulating our moods. Along with regulating when we are happy (or not), serotonin assists our body’s physical responses when we are experiencing those moods (like stress eating before a work meeting, sleeping better after spending all day with your favorite horse, or even making your bowels move to its own rhythm).
Now many of you might be thinking that serotonin comes from the limbic system. Right? Well, in this case, you would have to guess again. Serotonin starts in the digestive tract. You read that right. The digestive tract converts another well-known protein, tryptophan, into serotonin (a real link as to why Thanksgiving dinner makes us happy, and tired, all at the same time). This counts for over 90% of the serotonin production in our bodies! That darn amygdala really isn’t pulling its weight there.
Serotonin has a path a bit more easy to follow than the other neurotransmitters. Whether produced in the gut or the brain, serotonin travels through the adrenal gland system to the amygdala and the hypothalamus. Once both of them start saying “this feels nice,” it sends serotonin to the prefrontal cortex. Once there, the prefrontal cortex agrees it is time to feel good. It passes its good vibes off to the thalamus and the rest of the brain to help it feel relaxed. The hippocampus records all of this into a memory to help us be prepared for happiness in the future.
Fun facts about serotonin include its role in digestive and bone health. It is pretty obvious if we are stressed, our digestive health sucks. With that said, while our digestive tract is down, it isn’t digesting the minerals and vitamins needed for healthy bones. This means our bone health suffers if we are chronically stressed. Personally, I think that is pretty cool as it has taken about 9 months to heal my broken arm (Coincidence? Perhaps not. Even though I practice what I preach, I’m still a full-time wife, mom and therapist just trying to make time to snuggle a horse). Nonetheless, serotonin is impacted by our diet and what we eat. Foods rich in tryptophan and protein help boost serotonin levels (bring on daily Thanksgiving meals baby!).
Serotonin is by far the most well known neurotransmitter out of the bunch. Why? This is the main neurotransmitter associated with depression. When there isn’t enough serotonin in the brain, our bodies naturally become depressed. Many medications that are used to treat depression focus on how much serotonin is left in the synaptic gap. Sometimes, the medications leave too much serotonin in the gap. Is that a bad thing? You got it! Too much serotonin can lead to serotonin syndrome. The usual presentation of this is confusion, heavy sweating, loopy behavior, diarrhea, even high temperatures and seizures that can be life threatening. Yikes!
Talk about a whirlwind of information! You guys have shown some pretty amazing dedication to learning all the parts of what makes our brain do what it does. I want to thank you for taking the time to invest in your health and making your quality of life better. Next week, we are going to dive into the fight-flight-freeze response, which is a major part of any animal’s life, not just mental health.
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