A new study sheds light on why alcohol appears to cause different reactions when drinking in a group or alone.
- By studying fruit flies, researchers have understood why our reactions to alcohol differ depending on whether we drink alone or in a group.
- They noticed that dopamine levels spiked when alcohol was consumed in a social situation.
- The dopamine D1 receptor appears to play an important role in the response of flies to ethanol in a social environment.
“Social contexts influence how individuals respond to alcohol, but there is no research on how and why this happens”explains Kyung-An Han, a biologist at the University of Texas at El Paso (UTEP). Indeed, toasting with friends or having a drink alone at home does not provide the same sensations. The first situation is rather associated with positive feelings, the second with neutral or even negative emotions.
To understand how alcohol causes different reactions when consumed alone or in a group, researchers studied drunken fruit flies and identified the effects of the drinks on the brain.
Drinking in groups boosts dopamine
The team exposed fruit flies, either alone or in groups, to ethanol vapor and observed their behavior. While the insects that “drank alone” showed a slight increase in movement, those exposed to ethanol in groups had significantly increased speed and movement.
The scientists then wanted to test the role of dopamine in the response to alcohol. They compared the reactions of experimental flies with high levels of the happy hormone to normal flies, serving as a control group.
The team found that flies with normal and high dopamine levels had a similar response to ethanol in a solitary environment: a slight increase in activity. In contrast, when in a group, flies with high dopamine levels showed even greater hyperactivity than usual.
“We demonstrated that social cues and dopamine act together to increase flies’ response to ethanol.”concludes Kyung-An Han in a press release.
Alcohol and friends: the responsible dopamine receptor identified
But what exactly is going on in the brain? By studying the five dopamine receptors present in the organ, the researchers determined that the dopamine D1 receptor played the largest role in the flies’ response to ethanol in a social environment.
“The human D1 receptor gene is linked to alcohol use disorder, and this study provides experimental validation. For the team, identifying the D1 receptor is crucial because it gives researchers at UTEP and beyond a blueprint for follow-up studies.”explains the scientist whose article appeared in the journal Addiction Biology.
His colleague Paul Rafael Sabandal adds: “Our work provides scientific insights to support the idea that the brain interprets and processes a person’s social environment and converges that signal to the dopamine system that is also activated by alcohol consumption. This gives us, as researchers, insight into the area and components of the brain that may serve as a focal point for all the signals that contribute to alcohol use disorder.”
The researchers plan to continue their work to determine why the dopamine D1 receptor serves as a “connection point” for signals that respond to ethanol and are involved in social interactions and alcohol dependence.
