Serotonin, also known as 5-hydroxytryptamine (5-HT), is primarily found in three areas: the central nervous system (CNS), the gastrointestinal tract, and blood platelets. In the CNS, serotonergic neurons are primarily located in the raphe nuclei of the brainstem. In the gastrointestinal tract, serotonin is produced by enterochromaffin cells. Platelets store serotonin and release it upon activation to aid in clot formation.
