5-Hydroxytryptamine (5-HT)

Serotonin also called 5-hydroxytryptamine,  is primarily found in the gastrointestinal (GI) tract and central nervous system (CNS) of animals. Approximately 80 percent of the human body's total serotonin is located in the enterochromaffin cells in the gut, where it is used to regulate intestinal movements. 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; and in blood platelets where it helps to regulate hemostasis and blood clotting. In addition to animals, serotonin is also found in fungi and plants. 5-hydroxytryptamine(5-HT) is an important neurotransmitter made by neurons in the central nervous system. These functions are mediated by a large number of receptors.After it is released by a neuron, 5-HT activates receptors located on nearby neurons.