Alcoholic Mice Live to Drink
A new line of mice, bred to prefer alcohol over all other beverages, is expected to offer insight into the role genetics and lifestyle play in alcoholism. The mice drink more alcohol than other animal models and consume it in a fashion similar to humans: choosing alcohol over other options and binge drinking.
A study published in the journal Addiction Biology reports the mice reach blood-alcohol levels of more than 260 mg/dl of alcohol daily—over three times the equivalent of the human legal driving limit and the approximate consumption level that the severest human alcoholics attain.
“The free-choice drinking demonstrated by the new mouse line provides a unique opportunity to study the excessive intake that often occurs in alcohol-dependent individuals and to explore the predisposing factors for excessive consumption, as well as the development of physiological, behavioral and toxicological outcomes following alcohol exposure,” says senior author Nicholas Grahame, a biopsychologist specializing in alcoholism at Indiana University.
According to the National Institute on Alcohol Abuse and Alcoholism, part of the National Institutes of Health, an estimated 17.6 million Americans abuse alcohol or are alcohol dependent. Alcohol abuse and alcoholism can be treated but cannot be cured.
Mice share 80 percent of their genes with humans, so they are an excellent model to study alcoholism, a disease with a strong genetic component. The risk of developing alcoholism is known to be influenced by lifestyle. Animal models allow researchers to employ methods that they are unable to use in humans.
“This line of high-alcohol-seeking mice should be able to give us a better understanding of the basic brain mechanism involved in alcohol consumption as well as greater insight into the toxic effects on the brain, with the goal of developing therapies,” says Grahame, whose research focuses on behavioral genetics and behavioral pharmacology.
As with humans, the mice become intoxicated when the pace of alcohol consumption is faster than the liver can eliminate it. Typically it takes six or seven hours of continuous alcohol drinking for the new strain of mice to reach the highest levels of intoxication.
Doctoral candidate Liana M. Matson is a co-author of the study. She has conducted research focusing on when the mice drink and determined that they are nocturnal drinkers. This knowledge enabled the mice’s blood-alcohol levels to be tested when at their highest level.
Undergraduate School of Science students Amy Buckingham and Nick Villalta assisted in the research by measuring intake and blood-alcohol levels in the new strain of high-alcohol-seeking mice. In a related study, they analyzed how drunk the mice became by testing how the animals performed on a balance beam.
The research was funded by NIAAA and the School of Science at IUPUI.
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