Scientists at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) examined 13,000 food components to find out whether they stimulate the reward centre in the brain and make people feel good. Hordenine, which is found in malted barley and beer was identified as one of the substances that activate the dopamine D2 receptor.
According to the research, the feel-good effect of some foodstuffs is caused by the neurotransmitter dopamine – these foods stimulate the reward centre in the brain where the dopamine D2 receptor is located. Researchers at FAU investigated whether there are special substances in foods that activate the dopamine D2 receptor in the same way as dopamine.
The team worked with FAU’s Computer Chemistry Centre using a virtual screening approach that is often used in pharmaceutical research. This process analyses food components in a computer simulation rather than in the laboratory. Using computer simulations enables scientists to investigate all types of known substance whereas in the laboratory it is only feasible to test a small selection of foodstuff extracts using standard screening techniques.
Initially, the scientists set up a database of 13,000 molecules that occur in foodstuffs. Using this database, they identified molecules that fit the dopamine D2 receptor – rather like finding the right key for a lock. The system was then used to identify which molecules could interact with the dopamine D2 receptor; these might be present in synthetic substances already known to interact with the receptor, such as medicines for treating Parkinson’s and schizophrenia, or which might be candidates for interaction due to the three-dimensional structure of the receptor. 17 of the original 13,000 options were selected and these were analysed in the laboratory.
The most promising results were obtained for hordenine, a substance present in malted barley and beer. ‘It came as a bit of surprise that a substance in beer activates the dopamine D2 receptor, especially as we were not specifically looking at stimulant foodstuffs,’ explains Prof. Dr. Monika Pischetsrieder.
Just like dopamine, hordenine stimulates the dopamine D2 receptor, however it uses a different signalling pathway. In contrast with dopamine, hordenine activates the receptor solely through G proteins, potentially leading to a more prolonged effect on the reward centre of the brain. The team is now investigating whether hordenine levels in beer are sufficient to have a significant effect on the reward centre. The researchers state that their results indicate that hordenine may well contribute to the mood-boosting effect of beer.
Source: Scientific Reports: Sommer, Thomas; Hübner, Harald; El Kerdawy, Ahmed; Gmeiner, Peter; Pischetsrieder, Monika; Clark, Tim. Identification of the Beer Component Hordenine as Food-Derived Dopamine D2 Receptor Agonist by Virtual Screening a 3D Compound Database. Scientific Reports (2017), 7: 44201, DOI: 10.1038/srep44201. fau.eu/2017/09/25/news/research/beer-can-lift-your-spirits/