Global InformationTrace amine information
| Trace amine | |
|---|---|
| Drug class | |
 Phenethylamine skeleton | |
| Class identifiers | |
| Mechanism of action | Receptor agonist |
| Biological target | Human trace amine-associated receptor 1 |
| Chemical class | Endogenous amines with trace occurrence (nanograms or less per gram of brain tissue) |
| External links | |
| MeSH | C434723 |
| Legal status | |
| In Wikidata | |
Trace amines are an endogenous group of trace amine-associated receptor 1 (TAAR1) agonists[1] – and hence, monoaminergic neuromodulators[2][3][4] – that are structurally and metabolically related to classical monoamine neurotransmitters.[5] Compared to the classical monoamines, they are present in trace concentrations.[5] They are distributed heterogeneously throughout the mammalian brain and peripheral nervous tissues and exhibit high rates of metabolism.[5][6] Although they can be synthesized within parent monoamine neurotransmitter systems,[7] there is evidence that suggests that some of them may comprise their own independent neurotransmitter systems.[2]
Trace amines play significant roles in regulating the quantity of monoamine neurotransmitters in the synaptic cleft of monoamine neurons with co-localized TAAR1.[6] They have well-characterized presynaptic amphetamine-like effects on these monoamine neurons via TAAR1 activation;[3][4] specifically, by activating TAAR1 in neurons they promote the release[note 1] and prevent reuptake of monoamine neurotransmitters from the synaptic cleft as well as inhibit neuronal firing.[6][8] Phenethylamine and amphetamine possess analogous pharmacodynamics in human dopamine neurons, as both compounds induce efflux from vesicular monoamine transporter 2 (VMAT2)[7][9] and activate TAAR1 with comparable efficacy.[6]
Like dopamine, norepinephrine, and serotonin, the trace amines have been implicated in a vast array of human disorders of affect and cognition, such as ADHD,[3][4][10] depression[3][4] and schizophrenia,[2][3][4] among others.[3][4][10] Trace aminergic hypo-function is particularly relevant to ADHD, since urinary and plasma phenethylamine concentrations are significantly lower in individuals with ADHD relative to controls and the two most commonly prescribed drugs for ADHD, amphetamine and methylphenidate, increase phenethylamine biosynthesis in treatment-responsive individuals with ADHD.[3][11] A systematic review of ADHD biomarkers also indicated that urinary phenethylamine levels could be a diagnostic biomarker for ADHD.[11]
- ^ Panas MW, Xie Z, Panas HN, Hoener MC, Vallender EJ, Miller GM (December 2012). "Trace amine associated receptor 1 signaling in activated lymphocytes". J Neuroimmune Pharmacol. 7 (4): 866–76. doi:10.1007/s11481-011-9321-4. PMC 3593117. PMID 22038157.
Trace Amine Associated Receptor 1 (TAAR1) is a G protein coupled receptor (GPCR) that responds to a wide spectrum of agonists, including endogenous trace amines, ...
- ^ a b c Burchett SA, Hicks TP (August 2006). "The mysterious trace amines: protean neuromodulators of synaptic transmission in mammalian brain". Prog. Neurobiol. 79 (5–6): 223–46. doi:10.1016/j.pneurobio.2006.07.003. PMID 16962229. S2CID 10272684.
- ^ a b c d e f g Berry MD (January 2007). "The potential of trace amines and their receptors for treating neurological and psychiatric diseases". Rev Recent Clin Trials. 2 (1): 3–19. doi:10.2174/157488707779318107. PMID 18473983.
changes in trace amines, in particular PE, have been identified as a possible factor for the onset of attention deficit/hyperactivity disorder (ADHD) [5, 27, 43, 78]. PE has been shown to induce hyperactivity and aggression, two of the cardinal clinical features of ADHD, in experimental animals [100]. Hyperactivity is also a symptom of phenylketonuria, which as discussed above is associated with a markedly elevated PE turnover [44]. Further, amphetamines, which have clinical utility in ADHD, are good ligands at trace amine receptors [2]. Of possible relevance in this aspect is modafanil, which has shown beneficial effects in ADHD patients [101] and has been reported to enhance the activity of PE at TAAR1 [102]. Conversely, methylphenidate, which is also clinically useful in ADHD, showed poor efficacy at the TAAR1 receptor [2]. In this respect it is worth noting that the enhancement of functioning at TAAR1 seen with modafanil was not a result of a direct interaction with TAAR1 [102].
More direct evidence has been obtained recently for a role of trace amines in ADHD. Urinary PE levels have been reported to be decreased in ADHD patients in comparison to both controls and patients with autism [103-105]. Evidence for a decrease in PE levels in the brain of ADHD patients has also recently been reported [4]. In addition, decreases in the urine and plasma levels of the PE metabolite phenylacetic acid and the precursors phenylalanine and tyrosine have been reported along with decreases in plasma tyramine [103]. Following treatment with methylphenidate, patients who responded positively showed a normalization of urinary PE, whilst non-responders showed no change from baseline values [105]. - ^ a b c d e f Cite error: The named reference
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Millerwas invoked but never defined (see the help page). - ^ a b Eiden LE, Weihe E (January 2011). "VMAT2: a dynamic regulator of brain monoaminergic neuronal function interacting with drugs of abuse". Ann. N. Y. Acad. Sci. 1216 (1): 86–98. Bibcode:2011NYASA1216...86E. doi:10.1111/j.1749-6632.2010.05906.x. PMC 4183197. PMID 21272013.
[Trace aminergic] neurons in mammalian CNS would be identifiable as neurons expressing VMAT2 for storage, and the biosynthetic enzyme aromatic amino acid decarboxylase (AADC).
- ^ Grandy DK, Miller GM, Li JX (February 2016). ""TAARgeting Addiction"-The Alamo Bears Witness to Another Revolution: An Overview of the Plenary Symposium of the 2015 Behavior, Biology and Chemistry Conference". Drug Alcohol Depend. 159: 9–16. doi:10.1016/j.drugalcdep.2015.11.014. PMC 4724540. PMID 26644139.
TAAR1 is a high-affinity receptor for METH/AMPH and DA
- ^ Offermanns, S; Rosenthal, W, eds. (2008). Encyclopedia of Molecular Pharmacology (2nd ed.). Berlin: Springer. pp. 1219–1222. ISBN 978-3540389163.
- ^ a b Sotnikova TD, Caron MG, Gainetdinov RR (August 2009). "Trace amine-associated receptors as emerging therapeutic targets". Mol. Pharmacol. 76 (2): 229–35. doi:10.1124/mol.109.055970. PMC 2713119. PMID 19389919.
Although the functional role of trace amines in mammals remains largely enigmatic, it has been noted that trace amine levels can be altered in various human disorders, including schizophrenia, Parkinson's disease, attention deficit hyperactivity disorder (ADHD), Tourette syndrome, and phenylketonuria (Boulton, 1980; Sandler et al., 1980). It was generally held that trace amines affect the monoamine system indirectly via interaction with plasma membrane transporters [such as plasma membrane dopamine transporter (DAT)] and vesicular storage (Premont et al., 2001; Branchek and Blackburn, 2003; Berry, 2004; Sotnikova et al., 2004). ...
Furthermore, DAT-deficient mice provide a model to investigate the inhibitory actions of amphetamines on hyperactivity, the feature of amphetamines believed to be important for their therapeutic action in ADHD (Gainetdinov et al., 1999; Gainetdinov and Caron, 2003). It should be noted also that the best-established agonist of TAAR1, β-PEA, shared the ability of amphetamine to induce inhibition of dopamine-dependent hyperactivity of DAT-KO mice (Gainetdinov et al., 1999; Sotnikova et al., 2004).
Furthermore, if TAAR1 could be proven as a mediator of some of amphetamine's actions in vivo, the development of novel TAAR1-selective agonists and antagonists could provide a new approach for the treatment of amphetamine-related conditions such as addiction and/or disorders in which amphetamine is used therapeutically. In particular, because amphetamine has remained the most effective pharmacological treatment in ADHD for many years, a potential role of TAAR1 in the mechanism of the "paradoxical" effectiveness of amphetamine in this disorder should be explored. - ^ a b Scassellati C, Bonvicini C, Faraone SV, Gennarelli M (October 2012). "Biomarkers and attention-deficit/hyperactivity disorder: a systematic review and meta-analyses". J. Am. Acad. Child Adolesc. Psychiatry. 51 (10): 1003–1019.e20. doi:10.1016/j.jaac.2012.08.015. PMID 23021477.
Although we did not find a sufficient number of studies suitable for a meta-analysis of PEA and ADHD, three studies20,57,58 confirmed that urinary levels of PEA were significantly lower in patients with ADHD compared with controls. ... Administration of D-amphetamine and methylphenidate resulted in a markedly increased urinary excretion of PEA,20,60 suggesting that ADHD treatments normalize PEA levels. ... Similarly, urinary biogenic trace amine PEA levels could be a biomarker for the diagnosis of ADHD,20,57,58 for treatment efficacy,20,60 and associated with symptoms of inattentivenesss.59 ... With regard to zinc supplementation, a placebo controlled trial reported that doses up to 30 mg/day of zinc were safe for at least 8 weeks, but the clinical effect was equivocal except for the finding of a 37% reduction in amphetamine optimal dose with 30 mg per day of zinc.110
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