While many people have experienced that tipsy feeling after one too many cocktails, everyone reacts differently to alcohol as it enters the bloodstream and causes the all too familiar effects of intoxication.
This is why some people are done after one glass of wine while others have a higher tolerance for alcohol and can seem to drink in much higher quantities before showing any obvious signs of being drunk.
Many different factors impact alcohol sensitivity including body mass, genetic factors, and medical history.
However, one thing researchers were sure of was alcohol’s direct effect on the brain and body once it enters the bloodstream.
Now, a new study led by Scripps Research has found that there may be another step in the process that changes our understanding of how intoxication happens.
The study was published in the Journal of Molecular Biology, and the results show that alcohol travels to the nerve cells and attaches molecules to the membrane surface of a neuron that indirectly produces the effects of intoxication.
The researchers discovered this intermediary molecule step by studying inebriated fruit flies which have a similar reaction to alcohol that we as humans do.
“They act just like people,” said Scott Hansen, a co-author of the study. “They start losing coordination. They literally get drunk.”
Alcohol acts as an anesthetic and at first causes feelings of hyperactivity, or a “buzzed” feeling in both people and fruit flies.
The researchers tracked alcohol molecules as they traveled through the fruit flies by using previous anesthesia research.
A key part of the process, according to the researchers, has to do with an enzyme on the nerve cell membrane called phospholipase D2, (PLD2).
PLD2 allows alcohol molecules to attach to the membrane of the nerve cell and this in term creates a fatty alcohol metabolite called phosphatidylethanol (PEtOH).
After enough PEtOH metabolites build up on the nerve cell membrane, the neurons are able to fire easily which causes that “buzzed” sensation of hyperactivity.
Once the researchers silenced the gene expression that creates the PEtOH metabolite, the fruit flies did not become hyperactive after being exposed to alcohol.
Now, researchers have a pathway that can help determine alcohol sensitivity and the results could also produce insights into hangovers, according to the study.
“It has definitely led to some different ways of thinking about alcohol intoxication at the molecular level,’ said Hansen. “Most scientists thought alcohol had a direct effect. Blocking the enzyme in flies shows that’s not likely true.”