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Serotonin (5 hydroxytryptamine, 5-HT). is an excitatory neurotransmitter found in the Central Nervous System (CNS), especially in the hypothalamus and the mid-brain, yet much of it is found in the gastrointestinal tract. However it is also found in the blood platelets and mast cells. Serotonin arises in the brainstem from bunches of neurons known as the raphe nucleus. From the brain, serotonin neurons expand to virtually all parts of the CNS making the branching of the serotonin network the most expansive neurochemical system in the brain. The network importance is seen when each serotonin neuron exerts an influence over 500,000 target neurons. Since serotonin is so wide spread throughout the nervous system, it is no surprise that it can be linked to so many different types of behavior. Serotonin is an excitatory neurotransmitter. This is because the more serotonin that is in the receptors the greater affect it will have.

Where in Body Does it Affect? It has some effect on all parts of the body due to its involvement in the regulation of clotting factors. The most drastic impact it has is on the brain. This is particularly noticeable by serotonin’s ability to play a role in depression, anxiety, and obsessive compulsive disorder. Even though this is the most visible affect it has on the body, almost ninety percent of the body’s serotonin can be found in the gastrointestinal tract.

FUNCTIONS Serotonin can have many affects on a human. One affect is in a person and their sleep. Serotonin’s most noticeable function is the controlling of one’s mood. The level of serotonin in the body has a direct effect on it. This is partly why having low levels of serotonin can lead to alcoholism and drug abuse. The amount of serotonin in your body can also lead to depression. Serotonin can also play a role in the digestive system by helping muscles contract to push food through the digestive system. About ninety percent of the body’s serotonin is used for this purpose. Another function of serotonin is to help regulate the clotting factors of the blood when the body is bleeding.

Levels of Serotonin

Serotonin affects so many aspects of the human body that having high or low levels of serotonin can have various affects. High levels of serotonin can give someone a cheerful disposition while low levels can cause depression, anxiety, and obsessive compulsive disorder. Unfortunately, it can also cause diarrhea and low levels can cause constipation due to serotonin’s involvement in the digestive system. Also, a person has their lowest levels of serotonin when they are sleeping and their highest levels during the day and can affect how quickly someone can fall back to sleep.

Medications There are various medications that affect serotonin to improve someone’s mood. Examples of these include Prozac (fluoxetine), Zoloft (sertraline), and Paxil (paroxetine). These are known as SSRIs (selective serotonin reuptake inhibitors). They stop the reuptake of serotonin allowing it to improve somebody’s mood for a longer time. SSRIs are considered the first treatment for panic disorders. Many people who have depression take an SSRI in order to combat depression.

Interesting Facts 1. Eating bananas and walnuts can cause a temporary rise in serotonin levels because they contain tryptophan (a building block of serotonin). 2. Sunlight affects serotonin levels. This can cause people to experience depression during the winter due to lack of sunlight which causes lower serotonin levels. 3. Serotonin helps regulate body temperature and maintain pH levels in the body.

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By Andrew McDonald and Nick Maxwell


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