What is Histamine?
[[File:Brennnessel.jpg|thumb|The [[stinging nettle]] uses Histamine to protect itself. ]] '''Histamine''' is an [[organic]] [[nitrogen]]ous compound involved in local [[immune system|immune responses]]. It also regulates [[physiology|physiological]] function in the [[gut]], and acts as a [[neurotransmitter]].<ref>{{cite book |author=Marieb E. |title=Human anatomy & physiology |publisher=Benjamin Cummings |location=San Francisco |year=2001 |pages=414 |isbn=0-8053-4989-8 }}</ref> Histamine is involved in the [[inflammatory response]], where [[Tissue (biology)|tissues]] get red, swollen and painful. As part of an immune response to foreign [[pathogen]]s, histamine is produced by [[basophil]]s and by [[mast cell]]s found in nearby [[connective tissue]]s. Histamine increases the [[permeability]] of the [[capillary|capillaries]] to [[white blood cells]] and some [[proteins]]. The cells get through the walls of the tiny blood vessels to get at pathogens in the infected tissues.<ref>{{cite book |title=Nelson Biology 12 |url=https://archive.org/details/nelsonbiology12gius |author=Di Giuseppe M. | display-authors = etal |year=2003 |publisher=Thomson Canada |location=Toronto |isbn=0-17-625987-2 |page=[https://archive.org/details/nelsonbiology12gius/page/n373 473] }}</ref> Histamine in water exists as two tautomers in equilibrium, differing by the position of the hydrogen atom: [[File:Histamine tautomers.svg|thumb|center|400px|Tautomers of histamine]] == References == {{reflist}} {{Neurotransmitters}} [[Category:Hormones]] [[Category:Immunology]] [[Category:Organonitrogen compounds]]