3-Methoxytyramine

3-Methoxytyramine (3-MT), also known as 3-methoxy-4-hydroxyphenethylamine, is a human trace amine and the major metabolite of the monoamine neurotransmitter dopamine.^[1][2] It is formed by the introduction of a methyl group to dopamine by the enzyme catechol-O-methyltransferase (COMT). 3-MT can be further metabolized by the enzyme monoamine oxidase (MAO) to form homovanillic acid (HVA), which is then typically excreted in the urine.

3-Methoxytyramine

Names
Preferred IUPAC name 4-(2-Aminoethyl)-2-methoxyphenol
Other names 3-O-Methyldopamine
Identifiers
CAS Number	554-52-9 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:1582
ChemSpider	1606 N
ECHA InfoCard	100.122.789
IUPHAR/BPS	6642
MeSH	3-methoxytyramine
PubChem CID	1669
UNII	JCH2767EDP Y
CompTox Dashboard (EPA)	DTXSID40862189
InChI InChI=1S/C9H13NO2/c1-12-9-6-7(4-5-10)2-3-8(9)11/h2-3,6,11H,4-5,10H2,1H3 N Key: DIVQKHQLANKJQO-UHFFFAOYSA-N N InChI=1/C9H13NO2/c1-12-9-6-7(4-5-10)2-3-8(9)11/h2-3,6,11H,4-5,10H2,1H3 Key: DIVQKHQLANKJQO-UHFFFAOYAB
SMILES COc1cc(ccc1O)CCN
Properties
Chemical formula	C9H13NO2
Molar mass	167.21 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Occurrence

3-Methoxytyramine occurs naturally in the prickly pear cactus (genus Opuntia),^[3] and is in general widespread throughout the Cactaceae.^[4] It has also been found in crown gall tumors on Nicotiana sp.^[5]

In humans, 3-methoxytyramine is a trace amine that occurs as a metabolite of dopamine.^[1]

Biosynthetic pathways for catecholamines and trace amines in the human brain[6][7][8] L-Phenylalanine L-Tyrosine L-DOPA Epinephrine Phenethylamine p-Tyramine Dopamine Norepinephrine N-Methylphenethylamine N-Methyltyramine p-Octopamine Synephrine 3-Methoxytyramine AADC AADC AADC primary pathway PNMT PNMT PNMT PNMT AAAH AAAH brain CYP2D6 minor pathway COMT DBH DBH In humans, catecholamines and phenethylaminergic trace amines are derived from the amino acid L-phenylalanine.

Biological activity

Originally thought to be physiologically inactive, 3-MT was subsequently found to act as an agonist of the rodent and human TAAR1.^[1][9][2] 3-MT can induce weak hyperlocomotion in mice and this effect is partially attenuated in TAAR1 knockout mice.^[2][10]

See also

• Tyramine
• 3,4-Dimethoxyphenethylamine

References

1. Khan MZ, Nawaz W (October 2016). "The emerging roles of human trace amines and human trace amine-associated receptors (hTAARs) in central nervous system". Biomed. Pharmacother. 83: 439–449. doi:10.1016/j.biopha.2016.07.002. PMID 27424325.
2. Miller GM (January 2011). "The emerging role of trace amine-associated receptor 1 in the functional regulation of monoamine transporters and dopaminergic activity". Journal of Neurochemistry. 116 (2): 164–176. doi:10.1111/j.1471-4159.2010.07109.x. PMC 3005101. PMID 21073468. The data support the hypothesis that TAAR1 inhibits locomotor activity via a down-modulation of dopamine neurotransmission (Lindemann et al. 2008) and that the overruling effect of blocking TAAR1 is a net increase in the firing rate of DA neurons (Bradaia et al. 2009). However, a more recent study by Sotnikova et al. (2010) reports that the major extracellular metabolite of dopamine, 3-methoxytyramine, which is an agonist at rat TAAR1 (Bunzow et al. 2001), can induce mild hyperactivity in normal mice and a complex set of abnormal involuntary movements in normal mice acutely depleted of dopamine, and that these effects were attenuated in TAAR1 knockout mice. These data suggest that TAAR1 activation may stimulate locomotor activity. Collectively, the data illustrate a complexity of TAAR1 neurobiology that is still not fully understood.
3. Neuwinger HD (1996). "Cactaceae". African ethnobotany: poisons and drugs: chemistry, pharmacology, toxicology. CRC Press. p. 271. ISBN 978-3-8261-0077-2. Retrieved on June 12, 2009 through Google Book Search.
4. Smith T. A. (1977). "Phenethylamine and related compounds in plants". Phytochemistry. 16 (1): 9–18. Bibcode:1977PChem..16....9S. doi:10.1016/0031-9422(77)83004-5.
5. Mitchell S. D., Firmin J. L., Gray D. O. (1984). "Enhanced 3-methoxytyramine levels in crown gall tumours and other undifferentiated plant tissues". Biochem. J. 221 (3): 891–5. doi:10.1042/bj2210891. PMC 1144120. PMID 6477503.
6. Broadley KJ (March 2010). "The vascular effects of trace amines and amphetamines". Pharmacology & Therapeutics. 125 (3): 363–375. doi:10.1016/j.pharmthera.2009.11.005. PMID 19948186.
7. Lindemann L, Hoener MC (May 2005). "A renaissance in trace amines inspired by a novel GPCR family". Trends in Pharmacological Sciences. 26 (5): 274–281. doi:10.1016/j.tips.2005.03.007. PMID 15860375.
8. Wang X, Li J, Dong G, Yue J (February 2014). "The endogenous substrates of brain CYP2D". European Journal of Pharmacology. 724: 211–218. doi:10.1016/j.ejphar.2013.12.025. PMID 24374199.
9. Sotnikova TD, Beaulieu JM, Espinoza S, et al. (2010). "The dopamine metabolite 3-methoxytyramine is a neuromodulator". PLOS ONE. 5 (10): e13452. Bibcode:2010PLoSO...513452S. doi:10.1371/journal.pone.0013452. PMC 2956650. PMID 20976142.
10. Sotnikova TD, Beaulieu JM, Espinoza S, Masri B, Zhang X, Salahpour A, Barak LS, Caron MG, Gainetdinov RR (October 2010). "The dopamine metabolite 3-methoxytyramine is a neuromodulator". PLOS ONE. 5 (10): e13452. Bibcode:2010PLoSO...513452S. doi:10.1371/journal.pone.0013452. PMC 2956650. PMID 20976142.