Brain Facts:
Serotonin

Enterochromaffin Cells—
Chemotherapy

The enterochromaffin cells not only react to bad food, they are also very sensitive to irradiation and cancer chemotherapy. Drugs that block 5HT3 are very effective in controlling the nausea and vomiting produced by cancer treatment and are considered the gold standard for this purpose

Serotonin—
Diet

Serotonin levels are affected by diet. An increase in the ratio of tryptophan to phenylalanine and leucine will increase serotonin levels. 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.

Abu-Jayyab A. "Nutritional Pharmacology Of Sleep & Depression". SelfGrowth.com. article

Serotonin—
Gut, CNS

Approximately 80 percent of the human body's total serotonin is located in the enterchromaffin cells in the gut, where it is used to regulate intestinal movement.

The remainder is synthesized in serotonergic neurons in the CNS where it has various functions, including the regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions including memory and learning.

Serotonin—
Microanatomy

Serotonin is released into the space between neurons, and diffuses over a relatively wide gap (>20 µm) to activate 5-HT receptors located on the dendrites, cell bodies and presynaptic terminals of adjacent neurons.

Serotonin—
Microanatomy

Low levels of serotonin may also be associated with intense spiritual experience. Recent research conducted at Rockefeller University shows that, in both patients who suffer from depression and mice that model the disorder, levels of the p11 protein are decreased. This protein is related to serotonin transmission within the brain. Obsessive-compulsive disorder (OCD) can be a debilitating disorder with the following two anxiety-related essential features: obsessions (undesirable, recurrent, disturbing thoughts) and compulsions (repetitive or ritualized behaviors). SSRIs, and other medicines that alter serotonin levels have been approved for use in the treatment of symptoms of OCD.

Serotonin—
Neurotransmitter

Serotonin or 5-Hydroxytryptamine (5-HT) is a monoamine neurotransmitter, biochemically derived from tryptophan, that is primarily found in the gastrointestinal (GI) tract, platelets, and central nervous system (CNS) of humans and animals

Serotonin—
Pharmacological   Antidepressants

Modulation of serotonin at synapses is thought to be a major action of several classes of pharmacological antidepressants.

Serotonin—
Prescriptions

The most prescribed drugs in many parts of the world are drugs which alter serotonin levels.

Serotonin—
Sudden Infant Death Syndrome (SIDS)

In humans, defective signaling of serotonin in the brain may be the root cause of sudden infant death syndrome (SIDS). Scientists from the European Molecular Biology Laboratory in Monterotondo, Italy,] genetically modified lab mice to produce low levels of the neurotransmitter serotonin.

Although phobias and depression might be attenuated by serotonin-altering-drugs this does not mean that the individual's situation has been improved, but only the individual's perception of the environment. Sometimes a lower serotonin level might be beneficial, for example in the ultimatum game, where players with normal serotonin levels are more prone to accept unfair offers than participants whose serotonin levels have been artificially lowered.