Metabolismus

• Five prominent genera of Firmicutes (Blautia, Clostridium, Enterococcus, Ruminococcus, and Tyzzerella)
• Ability to abundantly produce aromatic amines
• Through the action of aromatic amino acid decarboxylase (AADC)
• In vitro cultivation of human fecal samples
• Significant positive correlation between aadc copy number of Ruminococcus gnavus and phenylethylamine (PEA) production
• Gut bacterial aadc stimulates the production of colonic serotonin
• Reportedly involved in osteoporosis and irritable bowel syndrome
• Human AADC inhibitors carbidopa and benserazide
• Inhibit PEA production in En. faecalis.

PEA has been shown to induce efflux of neurotransmitters (dopamine, norepinephrine, and serotonin) and inhibit uptake of these neurotransmitters in human cell lines and in brain synaptosomes from mouse, juvenile rhesus, and tamarin.Citation35 PEA activates polymorphonuclear leukocytes and induces allergic reactions.Citation36 These physiological effects of PEA are mediated by trace amine-associated receptor 1 (TAAR1) activation.Citation35,Citation36 Because TAAR1 is also expressed in the colonic epithelium,Citation37 PEA from gut bacteria is expected to exert physiological functions through TAAR1.Citation38 However, no studies have been conducted to investigate this possibility.https://www.tandfonline.com/doi/full/10.1080/19490976.2022.2128605

Metabolism

• PEA is metabolized by the cellular enzymes
• Fatty acid amide hydrolase (FAAH)
• N-acylethanolamine acid amide hydrolase (NAAA)
• More specificity toward PEA over other fatty acid amides