By hijacking memory formation pathways and changing the proteins expressed in neurons, alcohol alters memory formation at a fundamental molecular level.
This has been revealed through a study carried out at Brown University in the United States. Researchers used fruit flies as a model in their study, since the molecular signals involved in forming their reward and avoidance memories is fairly similar to the system in humans. Furthermore, fruit flies also seem to have a craving for alcohol. The fact that their brains have only 100,000 neurons in comparison to humans’ 100 billion, also means that their memory formation patterns are simple enough to study.
Explaining what the research was meant to find, Karla Kaun, assistant professor of Neuroscience at Brown University stated, “All drugs of abuse — alcohol, opiates, cocaine, methamphetamine — have adverse side effects. They make people nauseous or they give people hangovers, so why do we find them so rewarding? Why do we remember the good things about them and not the bad?”
According to the study, the primary culprit behind addiction formation in flies is a protein group known as Notch. These proteins trigger a signaling pathway involved in embryo development, brain development and adult brain function in various animals, including humans. The triggering of this pathway sets off a domino effect which influences the dopamine-2 receptor.
Emily Petruccelli from Southern Illinois University said, “The dopamine-2-like receptor is known to be involved in encoding whether a memory is pleasing or aversive.” And alcohol hijacks this conserved memory pathway to form cravings.
“We think these results are highly likely to translate to other forms of addiction, but nobody has investigated that,” said Kaun.
Currently, the team is using the same method to study the effect opiates have on the same molecular pathways. They are also observing DNA samples from patients with alcohol abuse disorders to see if they have genetic polymorphisms in any form of the craving related genes discovered in fruit flies.