View source for Monoamine neurotransmitter

{{Short description|Monoamine that acts as a neurotransmitter or neuromodulator}}
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[[File:Dopamine.svg|thumb|right|180px|[[Dopamine]]]]
[[File:Norepinephrine.svg|thumb|right|180px|[[Norepinephrine]]]]
[[File:Serotonin.svg|thumb|right|180px|[[Serotonin]]]]
'''Monoamine neurotransmitters''' are [[neurotransmitter]]s and [[neuromodulator]]s that contain one [[amino]] group connected to an [[aromaticity|aromatic ring]] by a two-carbon chain (such as -CH<sub>2</sub>-CH<sub>2</sub>-). Examples are [[dopamine]], [[norepinephrine]] and [[serotonin]].

All monoamines are derived from aromatic [[amino acid]]s like [[phenylalanine]], [[tyrosine]], and [[tryptophan]] by the action of [[aromatic amino acid decarboxylase]] [[enzyme]]s. They are deactivated in the body by the enzymes known as [[monoamine oxidase]]s which clip off the amine group.

Monoaminergic systems, i.e., the networks of neurons that use monoamine neurotransmitters, are involved in the regulation of processes such as emotion, arousal, and certain types of memory. It has also been found that monoamine neurotransmitters play an important role in the secretion and production of [[neurotrophin-3]] by astrocytes, a chemical which maintains neuron integrity and provides neurons with trophic support.<ref>{{cite journal |doi=10.1016/j.ijdevneu.2009.10.003 |title=Regulatory role of monoamine neurotransmitters in astrocytic NT-3 synthesis |year=2010 |last1=Mele |first1=Tina |last2=Čarman-Kržan |first2=Marija |last3=Jurič |first3=Damijana Mojca |journal=International Journal of Developmental Neuroscience |volume=28 |pages=13–9 |pmid=19854260 |issue=1|s2cid=25734591 }}</ref>

Drugs used to increase or reduce the effect of monoamine neurotransmitters are used to treat patients with psychiatric and neurological disorders, including [[Major depressive disorder|depression]], [[Anxiety disorder|anxiety]], [[schizophrenia]] and [[Parkinson's disease]].<ref name="pubmed21777827">{{cite journal |doi=10.1016/S1474-4422(11)70141-7 |title=The monoamine neurotransmitter disorders: An expanding range of neurological syndromes |year=2011 |last1=Kurian |first1=Manju A |last2=Gissen |first2=Paul |last3=Smith |first3=Martin |last4=Heales |first4=Simon JR |last5=Clayton |first5=Peter T |journal=The Lancet Neurology |volume=10 |issue=8 |pages=721–33 |pmid=21777827|s2cid=32271477 }}</ref>

== Examples ==
{{Catecholamine and trace amine biosynthesis|caption=Phenethylaminergic trace amines and the catecholamines are derivatives of L-phenylalanine.|align=right}}
{{transcluded section|source=Trace amine|part=yes}}
;Classical monoamines
* [[Imidazole]]amines:
** [[Histamine]]<ref name="pmid18989452">{{cite journal |vauthors=Romero-Calderón R, Uhlenbrock G, Borycz J, Simon AF, Grygoruk A, Yee SK, Shyer A, Ackerson LC, Maidment NT, Meinertzhagen IA, Hovemann BT, Krantz DE |title=A glial variant of the vesicular monoamine transporter is required to store histamine in the Drosophila visual system |journal=PLOS Genet. |volume=4 |issue=11 |article-number=e1000245 |date=November 2008  |pmid=18989452 |pmc=2570955 |doi=10.1371/journal.pgen.1000245 |quote=Unlike other monoamine neurotransmitters, the mechanism by which the brain's histamine content is regulated remains unclear. In mammals, vesicular monoamine transporters (VMATs) are expressed exclusively in neurons and mediate the storage of histamine and other monoamines. |doi-access=free }}</ref>
* [[Catecholamine]]s:
** [[Adrenaline]] (Ad; Epinephrine, Epi)
** [[Dopamine]] (DA)
** [[Noradrenaline]] (NAd; Norepinephrine, NE)
* [[Indolamines]]:
**[[Serotonin]] (5-HT)
**[[Melatonin]] (MT)

;Trace amines:
{{trim|{{:Trace amine}}}}

Specific transporter [[protein]]s called [[monoamine transporter]]s that transport monoamines in or out of a cell exist. These are the [[dopamine transporter]] (DAT), [[serotonin transporter]] (SERT), and the [[norepinephrine transporter]] (NET) in the outer [[cell membrane]] and the [[vesicular monoamine transporter]] ([[VMAT1]] and [[VMAT2]]) in the membrane of intracellular [[vesicle (biology)|vesicle]]s.{{citation needed|date=April 2013}}

After release into the [[synaptic cleft]], monoamine neurotransmitter action is ended by reuptake into the presynaptic terminal.  There, they can be repackaged into synaptic vesicles or degraded by the [[enzyme]] [[monoamine oxidase]] (MAO), which is a target of [[monoamine oxidase inhibitors]], a class of [[antidepressants]].{{citation needed|date=April 2013}}

==Evolution==
[[File:Monoamine receptor tree.svg|thumb|right|350px| A phylogenetic tree showing how a number of monoamine receptors are related to each other.]]
Monoamine neurotransmitter systems occur in virtually all vertebrates, where the evolvability of these systems has served to promote the adaptability of vertebrate species to different environments.<ref name="pmid14597267">{{cite journal | vauthors = Callier S, Snapyan M, Le Crom S, Prou D, Vincent JD, Vernier P | title = Evolution and cell biology of dopamine receptors in vertebrates | journal = Biology of the Cell | volume = 95 | issue = 7 | pages = 489–502 | year = 2003 | pmid = 14597267 | doi = 10.1016/s0248-4900(03)00089-3| s2cid = 18277786 | quote =  This "evolvability" of dopamine systems has been instrumental to adapt the vertebrate species to nearly all the possible environments.| doi-access = free }}</ref><ref name="pmid9916344">{{cite journal | vauthors = Vincent JD, Cardinaud B, Vernier P | title = [Evolution of monoamine receptors and the origin of motivational and emotional systems in vertebrates] | language = fr | journal = Bulletin de l'Académie Nationale de Médecine | volume = 182 | issue = 7 | pages = 1505–14; discussion 1515–6 | year = 1998 | pmid = 9916344 | quote = These data suggest that a D1/beta receptor gene duplication was required to elaborate novel catecholamine psychomotor adaptive responses and that a noradrenergic system specifically emerged at the origin of vertebrate evolution.
}}</ref>

A recent computational investigation of genetic origins shows that the earliest development of monoamines occurred 650 million years ago and that the appearance of these chemicals, necessary for active or participatory awareness and engagement with the environment, coincides with the emergence of bilaterian or "mirror" body in the midst of (or perhaps in some sense catalytic of?) the Cambrian Explosion.<ref>{{Cite journal |last1=Goulty |first1=Matthew |last2=Botton-Amiot |first2=Gaelle |last3=Rosato |first3=Ezio |last4=Sprecher |first4=Simon G. |last5=Feuda |first5=Roberto |date=2023-06-06 |title=The monoaminergic system is a bilaterian innovation |journal=Nature Communications |language=en |volume=14 |issue=1 |page=3284 |doi=10.1038/s41467-023-39030-2 |pmid=37280201 |issn=2041-1723|pmc=10244343 |bibcode=2023NatCo..14.3284G }}</ref> 
<!--==Disorders==-->

==See also==
*[[Monoamine reuptake inhibitor]]
*[[Monoamine receptor]]
* [[Monoamine oxidase]]
* [[Monoamine transporter]]
* [[Monoamine Hypothesis]]
* [[Biogenic amine]]
* [[Trace amine]]
* [[Monoamine nuclei]]
* [[Biology of depression]]

==References==
{{Reflist}}

==External links==
* {{MeshName|Biogenic+monoamines}}

{{Neurotransmitters}}
{{TAAR ligands}}

[[Category:Neurotransmitters]]
[[Category:TAAR1 agonists]]
[[Category:Amphetamine]]

[[fi:Hermoston välittäjäaine#Monoamiinit]]