Serotonin is a hormone that is active in the central nervous system. In the body, it is involved in a variety of processes, for example, it affects the perception of pain, memory, sleep and sexual behavior, and a person’s emotional state.
What is serotonin?
Serotonin is an important messenger substance (neurotransmitter) and a tissue hormone in the body. For example, it is found in the blood, gastrointestinal tract, central nervous system, and cardiovascular system. Neurotransmitters act in the nerve cells. There they meet receptors and trigger various functions and reactions. Serotonin was discovered in the organism in the late 1940s and has been intensively studied ever since. The messenger substance is very widespread in nature: In addition to the human organism, fungi, plants and even amoebae also produce the messenger substance.
Functions, tasks and meanings
Serotonin has a variety of functions and tasks in the human organism. Most serotonin is found in the stomach and intestinal tract. There, it regulates the important intestinal movements (peristalsis) necessary to digest food. In some cases, serotonin in the gastrointestinal tract can cause nausea and vomiting. The neurotransmitter also relays pain stimuli arising from discomfort in this area to the brain. Serotonin is also found in human blood. This is absorbed by the blood platelets from the vessels of the intestine. In the blood, serotonin has the function of constricting blood vessels. This is important, for example, when bleeding occurs. The constriction of the blood vessels helps the blood to clot, so that bleeding can be stopped more quickly by the body. In the eye, serotonin regulates intraocular pressure. The neurotransmitter is produced in the brain and is therefore found in the central nervous system. There, serotonin fulfills a wide variety of tasks and controls many different processes. For example, it regulates sleeping and waking behavior, body temperature, appetite, sexual behavior and pain perception. Among the best-known effects of serotonin is its impact on human mood. Depression can be caused by a lack of serotonin, but anxiety and aggression can also occur.
Diseases, ailments, and disorders
Not only a deficiency, but also an excess of serotonin can lead to a wide variety of complaints and disorders in the human body. In depression, there is often a deficiency of serotonin in the human cerebrospinal fluid (CSF). Drug therapy for depression is carried out using so-called serotonin inhibitors, which prevent serotonin from being broken down too quickly, thus making more serotonin available to the body. Similarly, a deficiency of serotonin is responsible for certain anxiety disorders and aggression. Indeed, its role as a neurotransmitter in the brain has to do with impulse control, among other things. In the case of a deficiency, this chemical reaction can no longer take place correctly, so that the disorders occur. Serotonin is directly related to food intake. It has an appetite suppressing effect. In overweight people, the level of serotonin in the brain is reduced. In patients with migraine, fluctuations in serotonin levels are observed before pain attacks, so the neurotransmitter is directly related to this condition. Serotonin levels drop sharply before attacks. In addition, scientists and doctors suspect that serotonin may be responsible for irritable bowel syndrome. However, this assumption has not yet been conclusively proven. Some tumors lead to an excess of serotonin in the body. In this so-called carcinoid syndrome, the tumor produces serotonin. As a result of the excess of serotonin, high blood pressure, shortness of breath and diarrhea occur. A possible cause of high blood pressure could be a disturbed serotonin level. Evidence suggests that certain drugs that have effects on serotonin levels may promote certain hypertensive disorders, such as pulmonary arterial hypertension. Serotonin is found in many foods, such as bananas, pineapples, and walnuts. However, this serotonin ingested through food cannot act in the brain because serotonin entering the blood through food cannot cross the blood-brain barrier. Only serotonin produced directly in the brain can act there and in the central nervous system.