Monkeys share many characteristics with humans – including our thirst for alcohol.
Medical researchers were able to turn eight rhesus monkeys into heavy drinkers by offering them increasing levels of alcohol.
With free access to alcohol throughout the day over a six-month period, it wasn’t long before the monkeys became veritable party animals, regularly binge-drinking.
The purpose of the research was to test a type of gene therapy currently used to treat Parkinson’s disease in hopes that it might one day help people with severe alcoholism.
“We know we can get people with an alcohol addiction to stop drinking for a short time,” says Kathleen Grant, a neuroscientist at Oregon Health & Science University. said Wired. “But the desire to drink again often takes the place of taking her medication.”
Grant and a team from several other research centers injected gene therapy into the brains of four of the eight alcoholic monkeys. The injections contained a growth factor protein called glia cell line-derived neurotrophic factor, or GDNF.
Previous studies have shown that GDNF can stimulate the production of dopamine, a neurotransmitter in the brain that plays a role in rewarding addictive behaviors.
Therefore, Grant and her colleagues used magnetic resonance imaging to guide the injection of GDNF into the ventral tegmental area of the brain, where neurons that produce dopamine and distribute it throughout the brain reside.
“It was incredibly effective,” Grant said in a press release. “Alcohol consumption went down to almost zero.
“For months, these animals drank water and abstained from alcohol altogether,” she added. “They reduced their alcohol consumption to the point where it was so low that we couldn’t measure blood alcohol levels.”
In addition, GDNF treatment has long-term benefits. After one year, the alcohol consumption of the four treated monkeys decreased by more than 90% compared to the control group of monkeys that did not receive the treatment.
“It was like learning that alcohol just wasn’t for them anymore,” Grant said.
Dopamine plays a crucial role in alcoholism. “Dopamine is involved in reinforcing behavior and helping people find certain things pleasurable,” Grant said.
“Acute alcohol consumption can increase dopamine levels. However, if you drink it regularly, the brain adapts to decrease the release of dopamine,” she added.
“So when people are addicted to alcohol, they don’t really enjoy drinking anymore. It seems they drink more because they feel the need to maintain a drunken state.”
The procedure is not yet ready for human trials, and even if it were used on humans, this type of brain surgery would only be used in the most severe cases of alcoholism.
That’s partly because the treatment is irreversible and permanently alters the brain, raising both medical and ethical questions.
“It would be best suited for people who have already shown that all of our usual therapeutic approaches are not working for them,” Grant said. “They are likely to cause serious harm or kill themselves or others as a result of their alcohol consumption.”
“This would be the last resort if all other treatment options fail.”
Alcoholism is a significant problem in the United States and around the world. An estimated 30 million Americans are living with an alcohol use disorder. according to the National Institute on Alcohol Abuse and Alcoholism.
The study, published in Nature Medicinewas also supported by researchers from Wake Forest University School of Medicine, Ohio State University and the University of California, San Francisco.