Serotonin

Serotonin or 5-hydroxytryptamine (5-HT) is a central nervous system chemical messenger involved in many physiological functions.

Serotonin is produced by a group of specific neurons which are therefore known as serotoninergic neurons. A fall in the activity of these neurons, and therefore in central serotoninergic transmission, is believed to be associated with certain forms of depression (particularly depression leading to suicide).