Excessive alcohol consumption at any age can have negative impacts on life. Whether these impacts be psychologically, behaviorally, socially, physically or emotionally to one’s life, they can be detrimental. As the brain still tends to be developing well into the mid-20s, these negative impacts seem to be even more crucial during the adolescent stage of an individual’s life.
Science Daily published an article called “Adolescent drinking affects adult behavior through long-lasting changes in genes” in 2015. This article describes the findings of researchers at the University of Illinois at Chicago College of Medicine and their study on rats to investigate the effects of alcohol exposure during the adolescent stage of development. Subhash Pandey, the lead researcher, said adolescence exposure to alcohol alters activity of genes which is needed for normal brain maturation. He believes these gene alterations ‘“increased anxiety-like behaviors and preference for alcohol in adulthood’” are behavioral effects that are due to epigenetic changes. Epigenetic changes regulate brain development and maturation resulting in changes to histones exposing the genes needed for new synaptic connection. In the experiment, the researchers gave 28 day old rats alcohol for two days in a row and two days off for 13 days. They found rats exposed to alcohol during adolescence drank more alcohol in adulthood and exhibited increased anxiety-like. Researchers analyzed tissue from the amygdala in the exposed rats and found tightly wrapped DNA and histones as well as increased levels of a protein, HDAC2 which modified histones to cause DNA to be wound tighter. All of the epigenetic changes observed were linked to lower expression of a gene needed to form new synaptic connections which persisted in adulthood. Overall, the alcohol affected rats exhibited a diminished nerve connectivity in the amygdala.
Recent studies have also experimented with rats to investigate the effects of alcohol consumption in adolescence including Jamie Donahey Roitman in “Consequences of Adolescent Ethanol Consumption on Risk Preference and Orbitofrontal Cortex Encoding of Reward”. As previous studies have associated consumption of alcohol in adolescence with increased impulsivity, Roitman believes this to be an effect caused by “long-term disruptions in cortical processing of rewards”. Roitman and researchers gave rats limited access to gelatin contained alcohol during their adolescent stage only. After the alcohol consumption in adolescence and while in adulthood, they recorded the electrophysiological activity while performing a task in the orbitofrontal cortex, which is associated with decision making. Multiple patterns were observed of the neuronal responses, but only one showed strongest modulation after reward and modulated by adolescent alcohol consumption. The neurons observed “showed blunted firing rates following rewards in alcohol-consuming rats, suggesting mechanism through which adolescent alcohol exposure may have lasting effects on reward processing in the context of decision making”. Overall it was observed that rats who consumed the higher levels of alcohol, compared to the control and low alcohol-consuming rats, exhibited increased risk preference. Roitman concluded that they identified a specific association between alcohol intake and function of the orbitofrontal cortex with this relationship persisting following the alcohol exposure.
Both the Science Daily article and Roitman’s paper expand on an experiment regarding adolescent consumption of alcohol and the effects. While the research done by Pandey focuses on the effects of certain genes, Roitman focuses on the neuronal responses in the orbitofrontal cortex. As Roitman concludes, alcohol consumption during the adolescence stage exhibits an increase of risk preference, this could be connected to Pandey’s belief that the gene alterations increase preference for alcohol in adulthood. Pandey concludes that alcohol consumption in adolescence diminishes nerve connectivity in the amygdala, which is thought to have the role of emotions and survival instincts. If Pandey finds a change in nerve connectivity, would Roitman’s technique be able to be used in this case to test the neuronal responses of the amygdala? Is there a relationship between the amygdala and the orbitofrontal cortex that causes this affect with alcohol? While the alcohol consumption would have to be similar to that given to the rats, both the experiments were able to find a connection and a poorly attributed effect with the consumption of alcohol in adolescence.
Resources:
Mcmurray, M. S., Amodeo, L. R., & Roitman, J. D. (2015). Consequences of Adolescent Ethanol Consumption on Risk Preference and Orbitofrontal Cortex Encoding of Reward. Neuropsychopharmacology, 41(5), 1366-1375. doi:10.1038/npp.2015.288
University of Illinois at Chicago. "Adolescent drinking affects adult behavior through long-lasting changes in genes." ScienceDaily. ScienceDaily, 2 April 2015. <www.sciencedaily.com/releases/2015/04/150402161505.htm>.
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