Studies using mice have discovered that adolescent binge drinking can lead to significant and lasting changes in the brain.
These findings suggest that heavy alcohol consumption during the teenage years can disrupt the normal functioning of brain cells and impair communication between them. This disruption has the potential to result in long-term changes in behavior and may provide insights into how alcohol affects cognition in humans.
Nikki Crowley, an assistant professor in biology and biomedical engineering, explained that when teenagers engage in excessive drinking, it can permanently alter the development of brain cells. Even if they stop drinking, these changes may be irreversible.
The prefrontal cortex, an essential region of the brain responsible for decision-making and risk assessment, is not fully developed in adolescents and continues to mature until around the age of 25. Disruptions to its development during this critical period can have severe and enduring consequences.
While binge drinking is detrimental to individuals of all ages and should be avoided, teenagers appear to be particularly vulnerable to its effects. The impact of heavy drinking during this stage of development can have long-lasting repercussions that extend well into adulthood.
To understand how binge drinking affects brain cells, a team led by Avery Sicher, a doctoral student in neuroscience, conducted experiments using a mouse model. The mice were exposed to alcohol in a manner that mimicked human binge drinking patterns, as defined by experts in alcohol abuse. This type of drinking is considered highly dangerous, and gaining insights into its impact on the developing brain can inform potential treatment strategies.
Over a period of 30 days, the mice were given access to alcohol, which roughly corresponds to the teenage years in humans due to their accelerated development. The researchers then examined the electrophysiological properties of various brain cells in the prefrontal cortex to observe how binge drinking during adolescence affected their activity and communication. They utilized advanced techniques such as whole-cell patch clamp electrophysiology and optogenetics to isolate individual neurons and measure their intrinsic excitability, including resting membrane potential and ability to generate action potentials. Through these methods, the researchers were able to analyze alterations in the signaling capabilities of the neurons.
The results of the study revealed that a specific group of brain cells known as somatostatin neurons, which play a crucial role in inhibiting the release of neurotransmitters and reducing neural noise, exhibited persistent dysregulation in the mice that engaged in binge drinking compared to those that only had access to water during their development. These neurons release inhibitory neurotransmitters such as GABA and somatostatin peptides, contributing to the healthy functioning of the brain. The binge-drinking mice displayed increased excitability in these neurons, leading to excessive signaling and dampening the activity of other important neurons. Interestingly, this hyperactivity persisted even after a 30-day abstinence period, when the mice had transitioned into adulthood.
Nikki Crowley further explained that neurons follow a fixed developmental trajectory, and disruptions during specific developmental periods can hinder their proper functioning. Consequently, the alterations caused by binge drinking during adolescence can have profound and long-lasting effects on brain function.
David Starnes, an undergraduate biology student, conducted cell counts to assess the density of somatostatin neurons before and after alcohol consumption. Interestingly, while the electrophysiology data suggested changes in the wiring of these neurons, the number of somatostatin neurons did not appear to be affected by binge drinking.
The research team consisted of various contributors, including graduate and undergraduate students, who worked under the support of the National Institutes of Health and the Huck Institutes of the Life Sciences at Penn State.
For those interested in learning more about Avery Sicher’s research in neuroscience, a video interview is available as part of the Huck Institutes’ Student Spotlight series. The full research paper is currently accessible online in the journal Neuropharmacology and is set to be published in the August 15th issue.