SEROTONIN 5 HYDROXYTRYPTAMINE
Before the identification of 5-hydroxytryptamine (5-HT), it was known that when blood is allowed to clot, a vasoconstrictor (tonic) substance is released from the clot into the serum. This substance was called serotonin. Independent studies established the existence of a smooth muscle stimulant in intestinal mucosa. This was called enteramine. The synthesis of 5-hydroxytryptamine in 1951 led to the identification of serotonin and enteramine as the same metabolite of 5-hydroxytryptophan.
Serotonin is an important neurotransmitter, a local hormone in the gut, a component of the platelet clotting process, and is thought to play a role in migraine headache and several other clinical conditions, including carcinoid syndrome. This syndrome is an unusual manifestation of carcinoid tumor, a neoplasm of enterochromaffin cells. In patients whose tumor is not surgically resectable, a serotonin antagonist may constitute a useful treatment.