Iidentification of the trace amine-associated receptor 1 (TAAR1) provided evidence for a direct biological effect of so-called trace amines (TAs) such as p-tyramine (pTyr), β-phenylethylamine (PEA), octopamine, and tryptamine. These biogenic amines previously denoted as false neurotransmitters, are metabolites of amino acids with structural similarity to classical biogenic amines. Although they are only found at low concentrations in the brain, TAs have been implicated in a wide range of neuropathological disorders, including schizophrenia, major depression, anxiety states, Parkinson's disease, and attention deficit hyperactivity disorder. TAAR1, a member of the TAAR family, is a G protein-coupled receptor that signals through Gs to elevate intracellular cAMP levels in response to TAs. It is expressed throughout the limbic and monoaminergic systems, including the ventral tegmental area (VTA) and dorsal raphe nucleus (DRN) and has been implicated in the negative modulation of monoaminergic neurotransmission[1].