Alzheimer’s drug Donepezil reverses brain damage in adolescent rats exposed to binge drinking, finds study
March 16, 2018 0 Comments
Scientific evidence shows that exposure to neurotoxins during adolescence, especially due to alcohol use, causes long-lasting structural and genetic changes in the brain. Much of the research has focused on the hippocampus, a brain region primarily associated with memory and learning. Excessive alcohol use during adolescence can cause lasting impairments to learning, memory and attention. However, there is limited research on the extent to which adolescents’ developing brains are impacted, and if the changes are permanent.
A recent study led by researchers from the Duke Health used a clinical rodent model to investigate the impact of adolescent intermittent ethanol (AIE) exposure, equivalent to drinking in excess of the legal driving limit 3-4 nights per week. The findings, published in the journal Alcoholism: Clinical and Experimental Research in February 2018, showed that adolescent rats exposed to alcohol for 16 days demonstrated a significant decline in the density of dendritic spines (mushroom-like protrusions emanating from neurons which help in transmitting signals).
To evaluate if the reduction in density of dendritic spines could be reversed, the researchers gave the alcohol-exposed rats Donepezil, a drug used for treating Alzheimer’s disease, for four days. The researchers subsequently reexamined the rats’ brains. It was found that the short-term drug intervention successfully restored dendritic spine density. The researchers also found that changes in the density of dendrites were linked to a gene called fragile X mental retardation 1 (FMR1).
Changes in the FMR1 gene are associated with degenerative or developmental disorders such as Parkinson’s disease and autism. According to the researchers, alcohol seemed to alter the regulation of the FMR1 gene in rats, which possibly reduced dendritic spine density. Donepezil reversed the changes in the FMR1 gene.
Adolescent alcohol use and cognitive function
According to the authors, while ongoing research continues to investigate the effect of alcohol on adolescents’ developing brains, the study’s findings have identified a definite brain function which is negatively impacted by alcohol, as well as a gene which appears to be central to reversing such detrimental impact. Lower dendritic spine density negatively impacts the information processing capabilities of brain cells, which in turn impairs memory and other cognitive functions. Moreover, the FMR1 gene also affects cognitive function, including memory and learning.
Donepezil belongs to a class of drugs called “cholinesterase inhibitors” which prevent the breakdown of acetylcholine, a chemical messenger regulating memory, learning and judgment. Alzheimer’s disease has the effect of destroying or damaging the cells which produce or use acetylcholine. Donepezil and other cholinesterase inhibitors help in maintaining acetylcholine levels and compensating for the loss of brain function. Research shows that chronic alcohol use can result in “alcohol-induced dementia.” Heavy alcohol use inhibits the release of acetylcholine in the hippocampus, which negatively impacts learning and memory.
Since it is unethical to recruit adolescent participants in scientific research involving binge drinking, most studies use animal models in lab settings. Since there are similarities in the hippocampi of humans and rodents, it often happens that the results of studies using rats are replicated in human trials. Moreover, it is sufficiently established that adolescent behavior is similar between humans and other mammalian species.
Risks of underage alcohol consumption
The Centers for Disease Control and Prevention (CDC) previously found that excessive alcohol consumption was responsible for the deaths of over 4,300 underage American youth. Although the legal drinking age in the United States is 21 years, people aged 12 to 20 drank 11 percent of the overall alcohol consumed nationwide. Binge drinking accounted for 90 percent of underage alcohol consumption. In 2016, nearly 7.3 million youngsters aged 12 to 20 (19.3 percent of the age group) reported using alcohol in the past month, while 4.5 million youth (12.1 percent) reported binge drinking.
Underage drinking increases the likelihood of academic problems, socio-legal problems, physical or sexual assault, unprotected sex, and unintentional injuries. It is also considered a gateway to using other drugs. Problematic alcohol use in adolescence can be treated with early intervention. White River Academy is a therapeutic boarding school for boys aged 12-17 years. We offer evidence-based treatment for alcohol addiction treatment for teens. If you know a teen boy addicted to alcohol, call our 24/7 helpline number or chat online to know more about the best residential alcohol addiction treatment centers for teens.