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Key Difference – Serotonin vs Endorphins

Serotonin and Endorphin are inhibitory neurotransmitters used by the nervous system to transmit signals from one neuron to another neuron and maintain a good connection between nerve cells. The key difference between the Serotonin and Endorphin is that Serotonin is a monoamine neurotransmitter while Endorphin is a small protein having a larger molecule. Both neurotransmitters are basically known as happiness molecules or the feel-good chemicals.

1. Overview and Key Difference
2. What is Serotonin
3. What are Endorphins
4. Side by Side Comparison – Serotonin vs Endorphins
5. Summary

What is Serotonin?

Serotonin, also known as 5-hydroxytryptamine, is a neurotransmitter which is involved in chemical signal transmission across nerve junctions within the nervous system. It is a monoamine, having the chemical formula of C10H12N2O as shown in figure 01. Serotonin is synthesized by serotonergic neurons in the brain and mostly found in the gastrointestinal tract, blood platelets and the central nervous system of the humans and other animals. A majority of the serotonins are gathered in gastrointestinal tract since its main function is associated with the GI tract (regulation of the intestinal movements). Tryptophan (an amino acid) is the precursor uses for biosynthesis of serotonin and the process is similar to the production of Dopamine. Synthesized serotonins are packed and stored in the synaptic vesicles at the axon terminal (presynaptic end of the neuron). When the presynaptic neuron receives an action potential by the stimulus, it releases serotonins to the synaptic cleft of the chemical synapse. Serotonins diffuse through the cleft and bind to serotonergic receptors called 5-HT receptors located on the membrane of the postsynaptic neuron (mainly on the dendrites) and transmit the signal to it. Serotonins are responsible for different functions in the body such as carbohydrate cravings, sleep cycle, pain control, appropriate digestion, social behavior, appetite, memory and sexual desire, and function, etc.

Serotonin action belongs to the inhibitory group of neurotransmitters since it does not stimulate the brain. This means serotonin is involved in stabilizing the mood and balancing the excessive stimulations of the brain. Low levels of serotonin will be responsible for depression, anxiety, anger and feeling of loneliness. A large amount of serotonin will give you positive feelings and make you relaxed. Excess amounts of serotonin will lead for a condition called serotonin syndrome.

Serotonin manufacturing can be enhanced by several factors which involve induction of tryptophan production. Those are healthy diets, medication, exercise, sunlight, etc. Depression due to low levels of serotonin in the body can be overcome by taking selective serotonin reuptake inhibitors (SSRI). It is a commonly prescribed antidepressant by doctors. SSRI will inhibit the reuptake of serotonin by presynaptic neurons and increase the activity of serotonin to bind to the 5-HT receptors on the postsynaptic neuron.

Difference Between Serotonin and Endorphins - 1

Figure_01: Structure of Serotonin 

What are Endorphins?

Endorphins are another type of neurotransmitters (which belong to the neuropeptide category) involved in the chemical signal transmission through chemical synapses within the nervous system. They are small proteins composed of larger molecular weight peptides (C45H66N10O15S) as shown in figure 02. Endorphins are mainly found in the pituitary gland and the brain. It is the main chemical responsible for pain relief (reduce the perception of pain). Since Endorphins act as painkillers, they can be considered as analgesics similar to morphine and codeine. This property is due to the inhibition of protein synthesis which is responsible for pain transmission through the body. Endorphins bind to opioid receptors located on the postsynaptic neurons and inhibit the transmission of pain signals.

Endorphins have several functions in the body including reduction of pain and stress, enhancement of the immune system, regulation of rewards system actions etc. Endorphins are inhibitory neurotransmitters present in the nervous system to fix the mood and calm the brain. Stress and pain are the main stimuli responsible for Endorphin release. Endorphins are released into the synaptic cleft and travel through the medium and bind with the opioid receptors of the postsynaptic end. Binding of endorphins to receptors will inhibit the generation of an action potential, making the membrane potential more negative.

Maintaining proper levels of Endorphin in the body is important since low levels caused by different conditions such as depression, low tolerance for pains, lack of enthusiasm, chronic pains, etc. Endorphin production can be induced by proper exercise, meditation, certain foods, acupuncture, etc.

Key Difference - Serotonin vs Endorphins

Figure_2: Structure of Endorphin

What is the difference between Serotonin and Endorphins

Serotonin vs Endorphins

Serotonin is a small molecule monoamine neurotransmitter. Endorphin is a small protein made up of peptides (neuropeptide).
Serotonin is found in the gastrointestinal tract. Endorphins are found in the pituitary gland.
Main Function
Serotonin maintains the mood balance. Endorphins reduce the perception of pains.
Binding Receptors
5-HT receptors act as binding receptors Opioid receptors act as binding receptors

Summary –  Serotonin vs Endorphins

Despite the difference between Serotonin and Endorphin, both are inhibitory neurotransmitters responsible for mood fixing and balancing the brain stimulations. Both can help a person to feel pleasure and relieve pains. Considering the major role of these neurotransmitters, Serotonin can be known as a good mood chemical while Endorphin is the pain relieving chemical found in our nervous system.

1.”Neurogistics.” What are Neurotransmitters? – Neurogistics. N.p., n.d. Web. 15 Feb. 2017
2.”Serotonin and Dopamine and How They Work In Our Brain.” New Health Advisor. N.p., 18 Jan. 2016. Web. 15 Feb. 2017
3.Sprouse-Blum, Adam S., Greg Smith, Daniel Sugai, and F. Don Parsa. “Understanding Endorphins and Their Importance in Pain Management.” Hawaii Medical Journal. University Clinical, Education & Research Associate (UCERA), Mar. 2010. Web. 15 Feb. 2017

Image Courtesy:
1.”Beta-neoendorphin” By Ed (Edgar181) – Own work (Public Domain) via Commons Wikimedia
2.”Serotonin-skeletal” By Harbinary – Own work (Public Domain) via Commons Wikimedia