Editing Catecholamine (section)

{{Short description|Class of chemical compounds}}
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|image1=Adrenalin - Adrenaline.svg
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|caption1=[[Epinephrine]] (adrenaline)
|image2=Noradrenalin - Noradrenaline.svg
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|caption2=[[Norepinephrine]] (noradrenaline)
|image3=Dopamin - Dopamine.svg
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|caption3=[[Dopamine]]
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[[Image:Pyrocatechol.svg|class=skin-invert-image|thumb|80px|[[Catechol]]]]

A '''catecholamine''' ({{IPAc-en|ˌ|k|æ|t|ə|ˈ|k|oʊ|l|ə|m|iː|n}}; abbreviated '''CA'''), most typically a '''3,4-dihydroxyphenethylamine''', is a [[monoamine neurotransmitter]], an [[organic compound]] that has a [[catechol]] ([[benzene]] with two [[hydroxyl]] side groups next to each other) and a [[Side chain|side-chain]] [[amine]].<ref>{{cite book | last = Fitzgerald | first = P. A. | chapter = Chapter 11. Adrenal Medulla and Paraganglia | editor1-last = Gardner | editor1-first = D. G. | editor2-last = Shoback | editor2-first= D. | title = Greenspan's Basic & Clinical Endocrinology | edition = 9th | location = New York | publisher = McGraw-Hill | year = 2011 | chapter-url = http://www.accessmedicine.com/content.aspx?aID=8404198 | access-date = October 26, 2011 }}</ref>

[[Catechol]] can be either a free molecule or a [[substituent]] of a larger molecule, where it represents a 1,2-dihydroxybenzene group.

Catecholamines are derived from the [[amino acid]] [[tyrosine]], which is derived from dietary sources as well as synthesis from [[phenylalanine]].<ref name="Purves">{{cite book |editor1-last=Purves |editor1-first=D. |editor2-last=Augustine |editor2-first=G. J. |editor3-last=Fitzpatrick |editor3-first=D. |editor4-last=Hall |editor4-first=W. C. |editor5-last=LaMantia |editor5-first=A. S. |editor6-last=McNamara |editor6-first=J. O. |editor7-last=White |editor7-first=L. E. | title = Neuroscience | edition = 4th | publisher = Sinauer Associates | pages = 137–138 | year = 2008 | isbn = 978-0-87893-697-7 }}</ref> Catecholamines are water-soluble and are 50% bound to plasma proteins in circulation.

Included among catecholamines are [[epinephrine]] (adrenaline), [[norepinephrine]] (noradrenaline), and [[dopamine]]. Release of the [[hormone]]s epinephrine and norepinephrine from the [[adrenal medulla]] of the [[adrenal gland]]s is part of the [[fight-or-flight response]].<ref>{{cite web | url = http://myhealth.ucsd.edu/library/healthguide/en-us/support/topic.asp?hwid=te7424 | publisher = University of California | location = San Diego, CA | work = Health Library | title = Catecholamines | url-status = dead | archive-url = https://web.archive.org/web/20110716025522/http://myhealth.ucsd.edu/library/healthguide/en-us/support/topic.asp?hwid=te7424 | archive-date = July 16, 2011 }}</ref>

Tyrosine is created from phenylalanine by [[hydroxylation]] by the enzyme [[phenylalanine hydroxylase]]. Tyrosine is also ingested directly from dietary protein. Catecholamine-secreting cells use several reactions to convert tyrosine serially to [[L-DOPA|<small>L</small>-DOPA]] and then to dopamine. Depending on the cell type, dopamine may be further converted to norepinephrine or even further converted to epinephrine.<ref>{{cite journal |last1=Joh |first1=T. H. |last2=Hwang |first2=O. | title = Dopamine Beta-Hydroxylase: Biochemistry and Molecular Biology | journal = Annals of the New York Academy of Sciences | volume = 493 | pages = 342–350 | year = 1987 | pmid = 3473965 | doi = 10.1111/j.1749-6632.1987.tb27217.x |s2cid=86229251 }}</ref>

Various [[stimulant]] drugs (such as a number of [[substituted amphetamine]]s) are catecholamine analogues.