Although the legal age for alcohol consumption is set at 21, teen drinking is widespread throughout the nation. A new study has found that intermittent teen drinking can cause permanent brain damage. The study was published online on April 27 in the journal Alcoholism: Clinical & Experimental Research by researchers at Duke University Medical Center (Durham, North Carolina) and Vanderbilt University (Nashville, Tennessee).
The study authors note that adolescence is a critical stage of neurological development, and sadly, it is also the period in which alcohol consumption is often at its highest. Alcohol abuse during the teen years may place the imbibers at heightened risk for subsequent alcohol abuse disorders, cognitive dysfunction, or other neurological impairments due to irreversibly altering long-term brain function. To assess the situation, the investigators modeled teen alcohol abuse via a rat model with intermittent alcohol exposure. The goal of the study was to determine whether adolescent exposure to alcohol can result in long-term structural and functional changes, which can be demonstrated in the adult brain.
The investigators specifically focused on a brain region known as hippocampal area CA1, which is associated with learning and memory. They conducted the analysis via electrophysiological, immunohistochemical, and neuroanatomical approaches. Post-alcohol changes in synaptic plasticity, dendritic spine morphology, and synaptic structure in adulthood were measured. All the foregoing measurements represent the network connections of brain cells.
The researchers found that adult rates exposed to alcohol during adolescence exhibited strong long-term potentiation, induced synaptic plasticity. (Synaptic plasticity is the ability of synapses (brain connections) to strengthen or weaken over time, in response to increases or decreases in their activity.) In addition, adolescent alcohol exposure resulted in an increased number of dendritic spines with characteristics typical of immaturity. (A dendritic spine is a small membranous protrusion from a brain cell’s dendrite that typically receives input from a single brain connection.) Immunohistochemistry-based examination of synaptic structures revealed a significant decrease in the number of postsynaptic puncta (structures surrounding the nucleus of the brain cells).
The study authors concluded that their study demonstrated that repeated alcohol exposure during the teen years results in persistent structural and functional abnormalities in the hippocampus. They noted that these synaptic changes in the hippocampal circuits may help explain learning-related behavioral changes in adult animals preexposed to alcohol.