Definition of "serotonin" [serotonin]

• An organic compound, C10H12N2O, formed from tryptophan and found in animal and human tissue, especially the brain, blood serum, and gastric mucous membranes, and active as a neurotransmitter and in vasoconstriction, stimulation of the smooth muscles, and regulation of cyclic body processes. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Anxiety and depression occur when too much serotonin is reuptaken and spends its time hiding in the nerve cells."
• "These experiments, which might have been the last performed by the hands of Jessell, led to the isolation of genes encoding the seven transmembrane domain serotonin receptor,"
• "If serotonin from the pineal does get back into the brain proper, it a must do so through such a circuitous route that many workers discredit this possibility."