Trace amines are compounds, such as p-tyramine and tryptamine, found in the body in trace amounts. These substances were believed to mainly modulate aminergic pathways. However, they were found to activate Trace amino associated receptors (TAARs), members of the G-protein coupled receptor (GPCRs) superfamily¹.

Trace amine receptor 1 (TAAR-1) is part of the Rhodopsin family of GPCRs. Five other putative genes are thought to encode TAAR receptors. This receptor has a seven transmembrane domain with short extracellular N- and intracellular C- terminal domains.

TAAR-1 couples G_s, thus leading to an increase in intracellular cAMP levels. Its signaling might be enhanced by monoamine transporters, and activation of TAAR-1 may also affect monoamine transport function. The receptor also inhibits PKA and PKC mediated dopamine uptake and PKC mediated dopamine efflux². It is also possible that it forms heterodimers with dopamine receptors, thus influencing dopamine transmission³.

In humans, this receptor is mainly expressed in the stomach but is also detected in the lungs, small intestine and many cerebral and cerebellar tissues including the amygdala, hypothalamus and others⁴.

In experiments conducted in mice it was shown that TAAR-1 knockout mice display increased stimulation effects of d-amphetamine, greater levels of extracellular monoamine and hyperactivity. These effects are related to clinical conditions such as ADHD, psychosis and other psychiatric problems⁵. Additional studies on TAAR family receptors may be helpful in finding cutting edge treatment.