[5] They are distributed heterogeneously throughout the mammalian brain and peripheral nervous tissues and exhibit high rates of metabolism.

[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.

[19] However, the rapid metabolic turnover of trace amines, consequent to strong susceptibility to monoamine oxidases, is suggestive that they may be present as chemical synapses at much higher concentrations than predicted by steady-state measures.

[19] A thorough review of trace amine-associated receptors that discusses the historical evolution of this research particularly well is that of Grandy.