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| Names | |
|---|---|
| Preferred IUPAC name 4-(2-Aminoethyl)-2-methoxyphenol | |
| Other names 3-O-Methyldopamine | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChemSpider |
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| ECHA InfoCard | 100.122.789 |
| MeSH | 3-methoxytyramine |
| UNII | |
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| Properties | |
| C9H13NO2 | |
| Molar mass | 167.21 g/mol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
3-Methoxytyramine (3-MT), also known as3-methoxy-4-hydroxyphenethylamine, is a humantrace amine and the majormetabolite of themonoamine neurotransmitterdopamine.[1][2] It is formed by the introduction of amethyl group to dopamine by theenzymecatechol-O-methyltransferase (COMT). 3-MT can be further metabolized by the enzymemonoamine oxidase (MAO) to formhomovanillic acid (HVA), which is then typically excreted in the urine.
3-Methoxytyramine occurs naturally in theprickly pear cactus (genusOpuntia),[3] and is in general widespread throughout theCactaceae.[4] It has also been found incrown gall tumors onNicotiana sp.[5]
In humans, 3-methoxytyramine is atrace amine that occurs as ametabolite ofdopamine.[1]
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Originally thought to be physiologically inactive, 3-MT was subsequently found to act as anagonist of the rodent and humanTAAR1.[1][9][2] 3-MT can induce weakhyperlocomotion in mice and this effect is partially attenuated in TAAR1knockout mice.[2][10]
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.
