Español
Questions About Cancer? 1-800-4-CANCER
  • Print
  • Facebook
  • Twitter
  • Google+
  • Pinterest

NCI Dictionary of Cancer Terms


serotonin  listen  (SAYR-uh-TOH-nin)

  A hormone found in the brain, platelets, digestive tract, and pineal gland. It acts both as a neurotransmitter (a substance that nerves use to send messages to one another) and a vasoconstrictor (a substance that causes blood vessels to narrow). A lack of serotonin in the brain is thought to be a cause of depression. Also called 5-hydroxytryptamine.