<unk> s (TAARs), sometimes referred to as<unk><unk>  receptors (TAs or TARs), are a class of G protein-coupled receptors that were discovered in 2001. TAAR1, the first of six functional human TAARs, has gained considerable interest in academic and proprietary pharmaceutical research due to its role as the endogenous receptor for the<unk><unk> s phenylethylamine, tyramine, and tryptamine – metabolic derivatives of the<unk>  acids phenylalanine, tyrosine and tryptophan, respectively – ephedrine, as well as the synthetic psychostimulants, amphetamine, methamphetamine and methylenedioxymethamphetamine (MDMA, ecstasy). In 2004, it was shown that mammalian TAAR1 is also a receptor for thyronamines, decarboxylated and deiodinated relatives of thyroid hormones. TAAR2–TAAR9 function as olfactory receptors for volatile<unk>  odorants in vertebrates. Figure 2: Table of ligands, expression patterns, and species-specific behavioral responses for each TAAR
Trace amine-associated receptor
Prolactin-releasing peptide receptor
Baroreceptor
Norepinephrine transporter
5-HT3 receptor
Glutamate transporter
Mechanosensitive channels
Gluten exorphin