Allylbenzene
Bluelighter
- Joined
- Jul 25, 2025
- Messages
- 984
There's also a phenethylamine accompanying ethanol in beer. Question is, is it present at relevant concentrations?
Hordenine (dimethyltyramine), a reversible MAO-B inhibitor, NRI and potentially a D2 agonist.
Animal study on hordenine from 2025. No D2 activity found.
Hordenine (dimethyltyramine), a reversible MAO-B inhibitor, NRI and potentially a D2 agonist.
https://www.nature.com/articles/srep44201D2R-promoted G-protein activation was observed for hordenine, a constituent of barley and beer, with approximately identical ligand efficacy as dopamine (76%) and a Ki value of 13 μM. Moreover, hordenine antagonised D2-mediated β-arrestin recruitment indicating functional selectivity.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9202863/One of the main sources of hordenine is germinated barley (Hordeum vulgare l.), which can release hordenine into beer during the brewing process. Several types of beer contain hordenine concentrations ranging from 1.0 to 6.3 mg/L, suggesting that beer consumption may contribute to a large proportion of dietary hordenine intake [5].
https://pubmed.ncbi.nlm.nih.gov/2570842/Studies, with selective irreversible inhibitors of MAO, showed that hordenine was a highly selective substrate for MAO-B of liver and that it was not deaminated by the MAO-A of intestinal epithelium.
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These results indicate that dietary-hordenine is unlikely to be deaminated by intestinal MAO as this is predominantly MAO-A. Consequently, it is likely to be absorbed and could affect the sympathetic nervous system, by virtue of its action as an inhibitor of noradrenaline uptake.
Animal study on hordenine from 2025. No D2 activity found.
Further characterization revealed monoaminergic binding sites of hordenine and found a strong binding on the serotonin and dopamine transporters, and dopamine D3, and adrenergic α1A and α2A receptor activation but no effects on GABAA receptor or glycinergic signalling.
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