serotonin

A vasoconstrictor, liberated by blood platelets, that inhibits gastric secretion and stimulates smooth muscle; present in relatively high concentrations in some areas of the central nervous system (hypothalamus, basal ganglia), and occurring in many peripheral tissues and cells and in carcinoid tumors. SYN: 5-hydroxytryptamine, enteramine, thrombocytin, thrombotonin. [sero- + G. tonos, tone, tension, + -in]

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se·ro·to·nin .sir-ə-'tō-nən, .ser- n a phenolic amine neurotransmitter C₁₀H₁₂N₂O that is a powerful vasoconstrictor and is found esp. in the brain, blood serum, and gastric mucous membrane of mammals called also 5-HT, 5-hydroxytryptamine

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n.

a compound widely distributed in the tissues, particularly in the blood platelets, intestinal wall, and central nervous system. Serotonin is thought to play a role in inflammation similar to that of histamine and it is involved in the genesis of a migrainous headache. Drugs that act like serotonin are used in the treatment of migraine (see 5HT1 agonist). It also acts as a neurotransmitter, and its levels in the brain are believed to have an important influence on mood. Drugs that prolong its effects are used as antidepressants (see SSRI).

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sero·to·nin (ser″o-toґnin) a monoamine vasoconstrictor, synthesized in the intestinal chromaffin cells or in central or peripheral neurons and found in high concentrations in many body tissues, including the intestinal mucosa, pineal body, and central nervous system. Produced enzymatically from tryptophan by hydroxylation and decarboxylation, it has many physiologic properties, such as inhibition of gastric secretion, stimulation of smooth muscle, serving as a central neurotransmitter, and being a precursor of melatonin. It is also found in animal species from coelenterates to vertebrates, in bacteria, and in many plants. Called also 5-hydroxytryptamine.