Anyone who has been part of the buzzing New Year celebrations knows that a little alcohol can make us euphoric, energetic and tender. But the more we drink, the more we fall into a (sometimes life-threatening) stupor. Scientists behind a recent study claim to have figured out how this initial buzzing feeling is going on, all thanks to some kind of drunken flies.
The study, published this month in the journal Molecular Biology, was prepared by scientists from the Scripps Research Institute, a non-profit research center and postgraduate studies in California and Florida.
Based on earlier studies, the team suggested that the drowsy effects of alcohol on the brain were similar to those of anesthesia. Therefore, they decided to carefully study the molecular pathway activated in nerve cells when we drink alcohol or undergo sedation, including the enzyme phospholipase D2 or PLD2. PLD2 is believed to help connect ethanol molecules to fat stored in the membrane or the surface of nerve cells. And they used fruit flies as a placeholder for humans, because flies seem to behave like we do when they absorb.
“They act like people,” said senior author Scott Hansen, an associate professor at the department of molecular medicine at Scripps, in a statement. “They start to lose coordination. They literally get drunk. ”
Hansen and his team placed the flies in a small tube and fed them liquid food dosed with alcohol, and the flies, as expected, began to buzz. Looking at the brain of these flies afterwards, they found that the activation of PLD2 through alcohol leads to a chain reaction of other processes inside the nerve cells. In particular, PLD2 splits alcohol into other molecules or metabolites, and one of these metabolites is a molecule consisting of fat and alcohol, called phosphatidyl ethanol (PEtOH). The accumulation of PEtOH, in turn, seems to induce nerve cells to start up faster, which means that their brain becomes hyperactive.
“With hyperactivity, you see that flies run more, and this is what we equate to be buzzing,” Hansen explained.
Hansen and his team also created flies, who had a gene that allowed their brain cells to recognize PLD2. These flies, in contrast to the unchanged flies, were not exaggerated at all, confirming their argument that PLD2 plays a key role in creating the initial buzzing sensation of drunkenness.
The authors argue that the results are particularly interesting, since it is believed that alcohol directly affects brain cells. But this would be an example of a drug indirectly affecting cells through the PLD2 pathway. This is important because we are obviously interested in stopping the worst effects of alcohol on people. So, perhaps drugs that can safely interact with PLD2 someday may prevent us from getting drunk in the first place, which can help people with alcohol dependence. Perhaps stopping PLD2 may even prevent other negative aspects of alcohol use, such as a severe hangover.
“This has definitely led to the emergence of various ways of thinking about alcohol intoxication at the molecular level,” said Hansen. “Most scientists believed that alcohol has a direct effect. Blocking the enzyme in flies shows that this is hardly true. ”
Fruit flies are a convenient substitute for humans, but, of course, their brains are not quite the same as ours. Thus, much work remains to be done to find out whether PLD2 is a key player in the excitation of people. Hansen and his team also plan to continue exploring how important PLD2 is to assist in creating other notorious effects of alcohol, including sedation.[Journal of Molecular Biology via Scripps]