A team of researchers from the University of Cologne along with colleagues from Mannheim and Heidelberg undertook a study to explore how even a single alcoholic drink can influence neuronal structure. The work, which appears in the Proceedings of the National Academy of Sciences, emphasizes that acute ethanol exposure can leave lasting impressions on neuron morphology at the cellular level.
Biologists have long proposed that even one episode of ethanol use can forge a positive association with drinking. To test this, the scientists used both fruit fly and mouse models. The results showed that a single ethanol dose disrupts the balance between mitochondrial dynamics and the connections between neurons, known as synapses, in brain cells. This disruption was correlated with measurable shifts in neuronal architecture that persisted after exposure.
Mitochondria supply the energy needed for cellular movement and the maintenance of cellular processes. Alcohol interfered with the transport of mitochondria within neurons and altered the biochemical balance across individual synapses. These changes remained stable over time and were accompanied by observable shifts in behavior in the animal subjects. In both flies and mice, exposure to alcohol at an early developmental stage led to a higher tendency to seek out alcohol later in life and a greater vulnerability to alcohol-related harm when exposures occurred again.
The remodeling of neuronal structure observed in these experiments is a recognized mechanism underlying learning and memory. As a result, some of the morphological alterations associated with ethanol exposure may influence how ethanol-related memories are formed and stored in the brain.
Researchers propose that the same cellular processes could contribute to the development of alcohol dependence in humans. A single intoxication event might set in motion enduring neural changes that influence future drinking patterns and the likelihood of relapse in later life, highlighting the potential for early-life experiences to shape long-term outcomes in alcohol use behavior.