histamine -
amine formed from histidine that stimulates gastric secretions and dilates blood vessels; released by the human immune system during allergic reactions
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues.
