Serotonin the neurotransmitter

Serotonin is a neurotransmitter

Neurotransmitters are chemicals that are used to relay, amplify and modulate signals between a neuron and another cell - cell to cell communicators

Serotonin is produced in the body from amino acids

Serotonin taken orally does not pass into the serotonergic pathways of the central nervous system because it does not cross the blood-brain barrier. However, tryptophan and its metabolite 5-hydroxytryptophan (5-HTP), from which serotonin is synthesized, can and does cross the blood-brain barrier. These agents are available as dietary supplements and may be effective serotonergic agents

Drugs may hinder the natural use/loss of serotonin but Drugs do not incease the supply of serotonin.

Serotonin levels may be increased by supplement of 5-hydroxitryptophan (5-HTP) and tryptophan. However, increasing foods rich in tryptophan (eg, meats, proteins) does not increase serotonin levels, due to competition with other amino acids. What is required to increase serotonin production is an increase in the ratio of tryptophan to phenylalanine and leucine. Fruits with a good ratio include dates, papaya and banana. Foods with a lower ratio inhibit the production of serotonin. These include whole wheat and rye bread. Much research has indicated that vigorous aerobic exercise improves mood, believed to be facilitated by an increase in serotonin levels. Research also suggests that eating a diet rich in whole grain carbohydrates and low in protein will increase serotonin by secreting insulin, which helps in amino acid competition. However, increasing insulin for a long period of time can sometimes onset insulin resistance, which is related to obesity, type 2 diabetes, and lower serotonin levels. It is also believed that muscles use many of the amino acids except tryptophan, allowing men to have more serotonin than women. Bright light therapy is another popular method which prevents the conversion of serotonin to melatonin. A similar effect is obtained by spending more time in natural sunlight. Recently, acupuncture has been shown to stimulate the release of serotonin levels in lab animals.

Serotonin plays an important role as a neurotransmitter in the modulation of anger, aggression, body temperature, mood, sleep, human sexuality, appetite, and metabolism, as well as stimulating vomiting.
Serotonin has broad activities and has been implicated in neurological diseases. Drugs targeting serotonin-induced pathways are being used in the treatment of many psychiatric disorders.
In addition, serotonin is found extensively in the gastrointestinal tract, about 80-90% of the body's total serotonin. In the blood, the major storage site is platelets, which collect serotonin for use in mediating post-injury vasoconstriction.
Recent research suggests that serotonin plays an important role in liver regeneration and acts as a mitogen (induces cell division) throughout the body.
Defective signalling of serotonin in the brain may be the root cause of sudden infant death syndrome (SIDS).