Editing Monoamine oxidase (section)

== Clinical significance ==
Because of the vital role that MAOs play in the inactivation of [[neurotransmitter]]s, MAO dysfunction (too much or too little MAO activity) is thought to contribute to a number of psychiatric and neurological disorders. Unusually high or low levels of MAOs in the body have been associated with [[schizophrenia]],<ref name="pmid943955">{{cite journal | vauthors = Domino EF, Khanna SS | title = Decreased blood platelet MAO activity in unmedicated chronic schizophrenic patients | journal = The American Journal of Psychiatry | volume = 133 | issue = 3 | pages = 323–6 | date = March 1976 | pmid = 943955 | doi = 10.1176/ajp.133.3.323 }}</ref><ref name="pmid1267046">{{cite journal | vauthors = Schildkraut JJ, Herzog JM, Orsulak PJ, Edelman SE, Shein HM, Frazier SH | title = Reduced platelet monoamine oxidase activity in a subgroup of schizophrenic patients | journal = The American Journal of Psychiatry | volume = 133 | issue = 4 | pages = 438–40 | date = April 1976 | pmid = 1267046 | doi = 10.1176/ajp.133.4.438 }}</ref> [[clinical depression|depression]],<ref name="pmid17088501">{{cite journal | vauthors = Meyer JH, Ginovart N, Boovariwala A, Sagrati S, Hussey D, Garcia A, Young T, Praschak-Rieder N, Wilson AA, Houle S | title = Elevated monoamine oxidase a levels in the brain: an explanation for the monoamine imbalance of major depression | journal = Archives of General Psychiatry | volume = 63 | issue = 11 | pages = 1209–16 | date = November 2006 | pmid = 17088501 | doi = 10.1001/archpsyc.63.11.1209 | doi-access =  }}</ref> [[attention deficit disorder]],<ref>{{cite journal | vauthors = Domschke K, Sheehan K, Lowe N, Kirley A, Mullins C, O'sullivan R, Freitag C, Becker T, Conroy J, Fitzgerald M, Gill M, Hawi Z | title = Association analysis of the monoamine oxidase A and B genes with attention deficit hyperactivity disorder (ADHD) in an Irish sample: preferential transmission of the MAO-A 941G allele to affected children | journal = American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics | volume = 134B | issue = 1 | pages = 110–4 | date = April 2005 | pmid = 15717295 | doi = 10.1002/ajmg.b.30158 | s2cid = 24453719 }}</ref>  [[substance abuse]],<ref>{{cite journal | vauthors = Oreland L | title = Platelet monoamine oxidase, personality and alcoholism: the rise, fall and resurrection | journal = Neurotoxicology | volume = 25 | issue = 1–2 | pages = 79–89 | date = January 2004 | pmid = 14697883 | doi = 10.1016/S0161-813X(03)00115-3 | bibcode = 2004NeuTx..25...79O }}</ref> migraines,<ref>{{cite journal | vauthors = Bussone G, Boiardi A, Cerrati A, Girotti F, Merati B, Rivolta G | title = Monoamine oxidase activities in patients with migraine or with cluster headache during the acute phases and after treatment with L-5-hydroxytryptophan | journal = Rivista di Patologia Nervosa e Mentale | volume = 100 | issue = 5 | pages = 269–74 | date = 1 October 2016 | pmid = 318025 }}</ref><ref>{{cite journal | vauthors = Filic V, Vladic A, Stefulj J, Cicin-Sain L, Balija M, Sucic Z, Jernej B | title = Monoamine oxidases A and B gene polymorphisms in migraine patients | journal = Journal of the Neurological Sciences | volume = 228 | issue = 2 | pages = 149–53 | date = February 2005 | pmid = 15694196 | doi = 10.1016/j.jns.2004.11.045 | s2cid = 572208 }}</ref> and irregular sexual maturation.{{citation needed|date=April 2013}} [[Monoamine oxidase inhibitor]]s are one of the major classes of drug prescribed for the treatment of depression, although they are often last-line treatment due to risk of the drug's interaction with diet or other drugs. Excessive levels of [[catecholamine]]s ([[epinephrine]], [[norepinephrine]], and [[dopamine]]) may lead to a [[Hypertensive emergency|hypertensive crisis]], and excessive levels of [[serotonin]] may lead to [[serotonin syndrome]].{{medical citation needed|date=May 2024}}

In fact, MAO-A inhibitors act as antidepressant and anti-anxiety agents, whereas MAO-B inhibitors are used alone or in combination to treat [[Alzheimer's disease]] and [[Parkinson's disease]].<ref name="pmid15279566">{{cite journal | vauthors = Riederer P, Lachenmayer L, Laux G | title = Clinical applications of MAO-inhibitors | journal = Current Medicinal Chemistry | volume = 11 | issue = 15 | pages = 2033–43 | date = August 2004 | pmid = 15279566 | doi = 10.2174/0929867043364775 | doi-broken-date = 2024-11-02 }}</ref>  Some research suggests that certain phenotypes of depression, such as those with anxiety, and "atypical" symptoms involving psychomotor retardation, weight gain and interpersonal sensitivity respond better to MAO inhibitors than other classes of anti-depressant.  However the findings related to this have not been consistent.<ref name="pmid32931110">{{cite journal | vauthors = Maj M, Stein DJ, Parker G, Zimmerman M, Fava GA, De Hert M, Demyttenaere K, McIntyre RS, Widiger T, Wittchen HU | title = The clinical characterization of the adult patient with depression aimed at personalization of management | journal = World Psychiatry | volume = 19 | issue = 3 | pages = 269–293 | date = October 2020 | pmid = 32931110 | pmc = 7491646 | doi = 10.1002/wps.20771 }}</ref> MAOIs may be effective in treatment resistant depression, especially when it does not respond to tricyclic antidepressants.<ref name="pmid15552546">{{cite journal | vauthors = Fiedorowicz JG, Swartz KL | title = The role of monoamine oxidase inhibitors in current psychiatric practice | journal = Journal of Psychiatric Practice | volume = 10 | issue = 4 | pages = 239–48 | date = July 2004 | pmid = 15552546 | pmc = 2075358 | doi = 10.1097/00131746-200407000-00005 }}</ref>

===Parasite interactions===
[[African trypanosomiasis|Sleeping sickness]] - caused by [[trypanosoma|trypanosomes]] - gets its name from the sleep disruption it causes in mammals. That sleep disruption is caused, at least in part, by trypanosomes' tendency to disrupt MAO activity in the [[orexin]] system.<ref name="Kristensson-et-al-2010" />

===Animal models===
There are significant differences in MAO activity in different species. Dopamine is primarily deaminated by [[monoamine oxidase A|MAO-A]] in rats, but by [[Monoamine oxidase B|MAO-B]] in [[vervet monkey]]s and humans.<ref name="Garrick Murphy">{{cite journal | vauthors = Garrick NA, Murphy DL | title = Species differences in the deamination of dopamine and other substrates for monoamine oxidase in brain | journal = Psychopharmacology | volume = 72 | issue = 1 | pages = 27–33 | year = 1980 | pmid = 6781004 | doi = 10.1007/bf00433804 | s2cid = 30722852 }}</ref>

Mice unable to produce either MAO-A or MAO-B display [[autism spectrum|autistic-like]] traits.<ref name="pmid22850464">{{cite journal | vauthors = Bortolato M, Godar SC, Alzghoul L, Zhang J, Darling RD, Simpson KL, Bini V, Chen K, Wellman CL, Lin RC, Shih JC | title = Monoamine oxidase A and A/B knockout mice display autistic-like features | journal = The International Journal of Neuropsychopharmacology | volume = 16 | issue = 4 | pages = 869–88 | date = May 2013 | pmid = 22850464 | pmc = 3517692 | doi = 10.1017/S1461145712000715 }}</ref> These [[Knockout mouse|knockout mice]] display an increased response to stress.<ref name="pmid14697877">{{cite journal | vauthors = Shih JC | title = Cloning, after cloning, knock-out mice, and physiological functions of MAO A and B | journal = Neurotoxicology | volume = 25 | issue = 1–2 | pages = 21–30 | date = January 2004 | pmid = 14697877 | doi = 10.1016/s0161-813x(03)00112-8 | bibcode = 2004NeuTx..25...21S }}</ref>

====Arthropods====
=====Insects=====
Insect brains express MAOs,<ref name="Gripois-et-al-1977" /><ref name="Evans-1980" /><ref name="Lund-et-al-1979" /> and some [[insecticide]]s<ref name="Aziz-Knowles-1973" /><ref name="Lund-et-al-1979" /> work by inhibiting them. An MAOI effect is especially important for [[chlordimeform]]<ref name="Aziz-Knowles-1973" /><ref name="Lund-et-al-1979" /><ref name="Beeman-Matsumura-1974" /> (although one result shows little or no effect in ''[[American cockroach|Periplaneta americana]]'');<ref name="Sloley-et-al-1985" /> and [[dieldrin]] may<ref name="Gripois-et-al-1977" /> or may not<ref name="Evans-1980" /> be an MAOI in ''[[migratory locust|Locusta migratoria]]''.{{medical citation needed|date=May 2024}}

=====Acari=====
MAO activity has been detected in ''[[Rhipicephalus microplus]]'' and chlordimeform is an MAOI in ''R. m.''.<ref name="Atkinson-et-al-1974" />