Meta-Tyramine Explained

meta-Tyramine, also known as m-tyramine and 3-tyramine, is an endogenous trace amine neuromodulator and a structural analog of phenethylamine.^{[1] [2] [3]} It is a positional isomer of para-tyramine, and similarly to it, has effects on the adrenergic and dopaminergic systems.^{[4] [5]}

meta-Tyramine is produced in humans via aromatic amino acid decarboxylase-mediated metabolism of meta-tyrosine.^[6] meta-Tyramine can be metabolized into dopamine via peripheral or brain CYP2D6 enzymes in humans.^[7]

See also

• para-Tyramine
• 3-Methoxytyramine

Notes and References

1. Boulton AA, Huebert ND . Biosynthesis of some urinary trace amines in the rat and the human . Research Communications in Chemical Pathology and Pharmacology . 34 . 2 . 295–310 . November 1981 . 7335956 .
2. Dyck LE, Juorio AV, Boulton AA . The in vitro release of endogenous m-tyramine, p-tyramine and dopamine from rat striatum . Neurochemical Research . 7 . 6 . 705–16 . June 1982 . 7121718 . 10.1007/bf00965523. 20758261 .
3. Sardar A, Juorio AV, Boulton AA . The concentration of p- and m-tyramine in the rat mesolimbic system: its regional distribution and effect of monoamine oxidase inhibition . Brain Research . 412 . 2 . 370–4 . June 1987 . 3607473 . 10.1016/0006-8993(87)91145-0. 34094088 .
4. Dyck LE, Kazakoff CW, Dourish CT . The role of catecholamines, 5-hydroxytryptamine and m-tyramine in the behavioural effects of m-tyrosine in the rat . European Journal of Pharmacology . 84 . 3–4 . 139–49 . October 1982 . 7173317 . 10.1016/0014-2999(82)90196-0.
5. McQuade PS, Wood PL . The effects of administration of meta-tyramine and para-tyramine on dopamine and its metabolites in the rat striatum . Progress in Neuro-psychopharmacology & Biological Psychiatry . 8 . 4–6 . 705–9 . 1984 . 6531442 . 10.1016/0278-5846(84)90042-3. 24889205 .
6. Encyclopedia: EC 4.1.1.28 – Aromatic-L-amino-acid decarboxylase (Homo sapiens). BRENDA. Technische Universität Braunschweig. 7 October 2016. July 2016. Substrate: m-tyrosine
   
   Product: m-tyramine + CO2
   
   Organism: Homo sapiens.
   Reaction diagram
7. Wang X, Li J, Dong G, Yue J . The endogenous substrates of brain CYP2D . Eur. J. Pharmacol. . 724 . 211–218 . February 2014 . 24374199 . 10.1016/j.ejphar.2013.12.025 . The highest level of brain CYP2D activity was found in the substantia nigra ... The in vitro and in vivo studies have shown the contribution of the alternative CYP2D-mediated dopamine synthesis to the concentration of this neurotransmitter although the classic biosynthetic route to dopamine from tyrosine is active. ... Tyramine levels are especially high in the basal ganglia and limbic system, which are thought to be related to individual behavior and emotion (Yu et al., 2003c). ... Rat CYP2D isoforms (2D2/2D4/2D18) are less efficient than human CYP2D6 for the generation of dopamine from p-tyramine. The K_m values of the CYP2D isoforms are as follows: CYP2D6 (87–121 μm) ≈ CYP2D2 ≈ CYP2D18 > CYP2D4 (256 μm) for m-tyramine and CYP2D4 (433 μm) > CYP2D2 ≈ CYP2D6 > CYP2D18 (688 μm) for p-tyramine.