The Science Behind the Serotonin Molecule That Makes Us Smile

Meet your new best friend. Serotonin, a neurotransmitter in your brain and produced in plants like the 4-lima bean, is among five compounds essential for life on Earth. It plays a role in eliciting mood, happiness, and well-being and acts as a growth factor for some places in the brain.

This article will examine what this mysterious molecule is all about and how it interacts with other neurotransmitters as part of the overall serotonin system (yes! There’s a system!).

What Is Serotonin?

Serotonin is a special thing in your brain that helps you feel happy and calm. It also helps your body handle things that make you feel scared or worried, like when you have to take a test or give a speech. It tells your body when to make certain hormones that help you feel better. So, serotonin helps you calm down and feel better when stressed.

Chemical Structure of Serotonin Molecule

The chemical structure of serotonin is somewhat complex, and it has been studied extensively by scientists. It is a monoamine neurotransmitter with inhibitory and excitatory effects on the central nervous system (CNS).

Biochemically derived from tryptophan, it is primarily found in the gastrointestinal tract (GI tract), platelets, and animals’ central nervous system (CNS), including humans. It is popularly thought to be a contributor to feelings of well-being and happiness.

Image Source: NCBI Bookshelf

A molecule of serotonin (C10H12N2O) contains a total of 24 atoms. Here is the breakdown of the atoms:

– Carbon (C): 10 atoms

– Hydrogen (H): 12 atoms

– Nitrogen (N): 2 atoms

– Oxygen (O): 1 atom

Adding up these atom counts gives a total of 10 + 12 + 2 + 1 = 24 atoms in a serotonin molecule.

Functional Groups of Serotonin

What is the answer to: what are functional groups of serotonin? Well, I’m going to tell you. Are you ready? Let’s begin.

1. Indole Ring: The central core of serotonin consists of an indole ring, a fused benzene ring, and a pyrrole ring structure. It provides the backbone of the molecule.

2. Amine Group: Serotonin contains an amine group (-NH2) attached to the indole ring at position 1. This amine group is responsible for serotonin’s classification as a monoamine neurotransmitter.

3. Hydroxyl Group: A hydroxyl group (-OH) is attached to the benzene ring of the indole structure at position 5. This hydroxyl group is involved in various interactions and can contribute to serotonin’s chemical and biological properties.

4. Ethyl Side Chain: At position 2 of the indole ring, an ethyl side chain (C2H5) is attached to the nitrogen atom. This side chain extends from the indole ring and contributes to the overall structure of serotonin.

These functional groups play essential roles in serotonin’s interactions with receptors, enzymes, and other molecules in the body, influencing its physiological functions and effects.

Synthesis of Serotonin Molecule

Did you know that serotonin is made in your body through several steps? It all starts with a special amino acid called tryptophan, which you get from your diet. This amino acid is transported to your brain and other tissues to turn it into serotonin.

The first step in making serotonin is when tryptophan is converted into 5-hydroxytryptophan (5-HTP) by an enzyme called tryptophan hydroxylase. Then, another enzyme called aromatic L-amino acid decarboxylase turns 5-HTP into serotonin.

After it’s made, serotonin is stored in special parts of your nerve cells called vesicles. When your nerve cells get stimulated, the serotonin is released into a small space between the cells called the synaptic cleft.

Making serotonin is complex and is influenced by many factors, like how much tryptophan is available and how active the enzymes are. Most of the serotonin in your body is made in your brain and gut, but it’s also in other parts of your body, like your blood and immune cells.

Serotonin Receptors in the Brain and Body

Serotonin receptors are these cool little proteins that hang out on the surface of cells in both our brains and bodies. They’re like little magnets that attract serotonin molecules and help transmit their signals, which can greatly impact how our bodies function.

These receptors are everywhere in our brains and regulate our moods, emotions, and thoughts. There are different types of serotonin receptors, like 5-HT1 and 5-HT2, and each type has unique subcategories. For example, 5-HT1A receptors can be found throughout the brain and help with anxiety, stress, and mood regulation.

When these receptors get activated, they can help calm us down and make us feel better. On the flip side, 5-HT2A receptors are mainly found in the outer layer of the brain (called the cortex) and are involved in processes like perception, hallucinations, and mood disorders.

But here’s the really wild part – serotonin receptors aren’t just in our brains. They’re also found in other parts of our bodies, like our digestive tract, blood vessels, and other tissues. In our digestive tract, serotonin receptors help regulate how our intestines move, how much they secrete, and how much pain we feel.

What Happens to Serotonin Molecules After Agonist Binding?

After a serotonin agonist binds to a serotonin receptor, several things can happen to the serotonin molecule:

1. Activation Station: When a serotonin agonist binds to a serotonin receptor on a target cell’s surface, it activates the receptor and sets off a chain reaction of intracellular signaling events.

2. Message Delivery: The activated serotonin receptor triggers different signaling pathways in the cell, which can lead to all sorts of cellular responses. This can involve activating enzymes, changing gene expression, or even affecting ion channels.

3. Brain Buzz: If the serotonin agonist is working in the central nervous system (CNS), it can boost neurotransmission by mimicking the effects of serotonin. This can cause more serotonin to be released from presynaptic neurons and/or keep postsynaptic receptors activated for longer.

4. Recycling or Breaking Down: Once the serotonin agonist has done its job, the serotonin molecule can be taken back up into the presynaptic neuron through reuptake. From there, it can either be repackaged for future use or broken down by enzymes like monoamine oxidase (MAO).

5. Clean Sweep: Any remaining serotonin molecules not taken back by the presynaptic neuron may be cleared from the extracellular space. This can happen in a few ways, like diffusing into nearby cells, being taken up by glial cells, or breaking down by enzymes like MAO.

Related Read: These are the foods you should eat to raise your serotonin levels

DMT vs. Serotonin Molecule

Some people might have talked about Dimethyltryptamine (DMT) and serotonin. They can be found in the same location in your brain and mimic similar effects. While there are many similarities, there are differences that, if you don’t understand risks, make a huge difference in your brain chemistry.

While DMT and serotonin share some structural similarities, their functions, occurrence, and effects are distinct. 

Serotonin is a naturally occurring neurotransmitter and hormone involved in various physiological processes, while DMT is a powerful hallucinogen that can produce intense psychedelic experiences.

Wrapping Up

The human body is complex but amazingly intriguing. The functions of the brain and its many neurotransmitters, for example, have long been the subject of study. (One molecule in particular, a class of neurotransmitters called monoamines, has been the focus of many studies.) 

And what researchers have found is that low serotonin levels can affect how we function daily. Luckily, there are ways you can increase this essential neurotransmitter to improve your mood and overall wellness.