Trace amine-associated receptors (nomenclature as agreed by NC-IUPHAR for trace amine receptors, [3]) were initially discovered as a result of a search for novel 5-HT receptors [1], where 15 mammalian orthologues were identified and divided into two families. Emerging evidence suggests that TA₁ is a modulator of monoaminergic activity in the brain [6] with TA₁ and dopamine D₂ receptors shown to form constitutive heterodimers when co-expressed [2].

See also TAAR2 (referred to in GRAC as TA₂).

TAAR3 (BO107, ENSMUSG00000069708, ENSRNOG00000025982), in some individuals, and TAAR4 (ENSMUSG00000069707, ENSRNOG00000029877) are pseudogenes in man, although functional in rodents. The signalling characteristics and pharmacology of TAA₅ (PNR, Putative Neurotransmitter Receptor, ENSG00000135569), TAA₆ (Trace amine receptor 4, TaR-4, ENSG00000146383), TAA₈ (Trace amine receptor 5, GPR102, ENSG00000146385) and TAA₉ (trace amine associated receptor 9, ENSG00000188604) are lacking. The thyronamines, endogenous derivatives of thyroid hormone, have been shown to have affinity for rodent cloned trace amine receptors, including TA₁ [4]. An antagonist EPPTB has recently been described that has a pK_i of 9.1 at the mouse TA₁ but less than 5.3 for human TA₁ [5].

Burchett, SA; Hicks, TP. (2006) The mysterious trace amines: protean neuromodulators of synaptic transmission in mammalian brain. Prog. Neurobiol., 79 (5-6): 223-46. [PMID:16962229]

Grandy, D. K. (2007) Trace amine-associated receptor 1-Family archetype or iconoclast?. Pharmacol Ther, 116: 355-390. [PMID:17888514]

Maguire, JJ; Parker, WA; Foord, SM; Bonner, TI; Neubig, RR; Davenport, AP. (2009) International Union of Pharmacology. LXXII. Recommendations for trace amine receptor nomenclature. Pharmacol. Rev., 61 (1): 1-8. [PMID:19325074]

Miller, GM. (2011) The emerging role of trace amine-associated receptor 1 in the functional regulation of monoamine transporters and dopaminergic activity. J. Neurochem., 116 (2): 164-76. [PMID:21073468]

Sotnikova, TD; Caron, MG; Gainetdinov, RR. (2009) Trace amine-associated receptors as emerging therapeutic targets. Mol. Pharmacol., 76 (2): 229-35. [PMID:19389919]

Zucchi, R., Chiellini, G., Scanlan, T. S. and Grandy, D. K. (2006) Trace amine-associated receptors and their ligands. Br J Pharmacol, 149: 967-978. [PMID:17088868]

1. Borowsky, B., Adham, N., Jones, K. A., Raddatz, R., Artymyshyn, R., Ogozalek, K. L., Durkin, M. M., Lakhlani, P. P., Bonini, J. A., Pathirana, S., Boyle, N., Pu, X., Kouranova, E., Lichtblau, H., Ochoa, F. Y., Branchek, T. A. and Gerald, C. (2001) Trace amines: identification of a family of mammalian G protein-coupled receptors. Proc Natl Acad Sci U S A, 98: 8966-8971. [PMID:11459929]

2. Espinoza, S; Salahpour, A; Masri, B; Sotnikova, TD; Messa, M; Barak, LS; Caron, MG; Gainetdinov, RR. (2011) Functional interaction between trace amine-associated receptor 1 and dopamine D2 receptor. Mol. Pharmacol., 80 (3): 416-25. [PMID:21670104]

3. Maguire, JJ; Parker, WA; Foord, SM; Bonner, TI; Neubig, RR; Davenport, AP. (2009) International Union of Pharmacology. LXXII. Recommendations for trace amine receptor nomenclature. Pharmacol. Rev., 61 (1): 1-8. [PMID:19325074]

4. Scanlan, T. S., Suchland, K. L., Hart, M. E., Chiellini, G., Huang, Y., Kruzich, P. J., Frascarelli, S., Crossley, D. A., Bunzow, J. R., Ronca-Testoni, S., Lin, E. T., Hatton, D., Zucchi, R. and Grandy, D. K. (2004) 3-Iodothyronamine is an endogenous and rapid-acting derivative of thyroid hormone. Nat Med, 10: 638-642. [PMID:15146179]

5. Stalder, H; Hoener, MC; Norcross, RD. (2011) Selective antagonists of mouse trace amine-associated receptor 1 (mTAAR1): discovery of EPPTB (RO5212773). Bioorg. Med. Chem. Lett., 21 (4): 1227-31. [PMID:21237643]

6. Xie, Z; Miller, GM. (2009) Trace amine-associated receptor 1 as a monoaminergic modulator in brain. Biochem. Pharmacol., 78 (9): 1095-104. [PMID:19482011]