What is serotonin?
Serotonin is a so-called neurotransmitter: it is a messenger substance that transmits information from one nerve cell to another in our nervous system. Serotonin is found in both the central and peripheral nervous systems. It is also found in blood platelets (thrombocytes) and in large quantities in special cells of our gastrointestinal tract.
Serotonin: formation, breakdown and excretion
The finished serotonin is then stored in small storage vesicles and released from there as needed. After release, it is reabsorbed via a 5-HT transporter and partly fed to the storage vesicles, partly broken down. This occurs with the help of various enzymes such as monoamine oxidase A (MAO-A). The end product of serotonin degradation is the so-called 5-hydroxyindoleacetic acid, which is then excreted in the urine.
Serotonin action
- Body temperature
- Appetite
- Emotions
- Central Reward System
- Mood and drive
- Level of consciousness and sleep-wake rhythm
- Pain assessment
Outside the brain, the neurotransmitter influences the widening of blood vessels, the bronchial tubes and the intestines. It also stimulates blood platelets (thrombocytes) and thus plays an important role in blood clotting.
Serotonin: Foods influence serotonin levels
When to determine serotonin?
Serotonin levels are determined primarily when the physician suspects a disease-related excess of the hormone due to a hormone-producing tumor. Such a carcinoid usually develops in the gastrointestinal tract, but can also develop in other parts of the body. Possible symptoms include:
- Flushing (reddening of the face and feeling of heat)
- palpitations
- watery diarrhea
- cramps (spasms) of the respiratory tract (bronchospasms)
Serotonin Reference Values
When is the serotonin level lowered?
Some physicians suspect that the development of some mental illnesses (such as depression or anxiety disorders) is related to a lowered serotonin level. So far, however, these are merely theories, and no significant proof has been found.
Serotonin Deficiency
If you want to learn more about how serotonin deficiency occurs and what it triggers in the body, read the article Serotonin Deficiency.
An elevated level of hydroxyindoleacetic acid (HIES) and thus of serotonin can indicate, above all, a carcinoid syndrome. Measured values of more than 40 milligrams of HIES in 24-hour collected urine are considered evidence of such a tumor.
However, an elevated HIES level can also occur in epilepsy and celiac disease (sprue).