Tyramine and -phenylethylamine, from fermented food products, as agonists for the human trace amine-associated receptor 1 (hTAAR1) in the stomach

The aromatic amines tyramine and -phenylethylamine are abundant in fermented foods. Recently, a family of human trace amine-associated receptors (hTAARs) was discovered that responds to these compounds. This study examined the expression of hTAAR genes in five human organs. Among them, the stomach expressed hTAAR1 and hTAAR9. Interestingly, more hTAAR1 was expressed in the pylorus than in the other stomach regions. The CRE-SEAP reporter assay revealed that only hTAAR1 functioned as a G(s)-coupled receptor in response to tyramine and -phenylethylamine stimulation. The -phenylethylamine-mediated hTAAR1 activity could be potentiated using 3-isobutyl-1-methylxanthine. These data suggest that tyramine and -phenylethylamine in fermented foods act at hTAAR1 as agonists in the pylorus of stomach.