Drinking alcohol shrinks critical brain regions in genetically vulnerable mice

February 15, 2012

Brain scans of two strains of mice imbibing significant quantities of alcohol reveal serious shrinkage in some brain regions - but only in mice lacking a particular type of receptor for dopamine, the brain's "reward" chemical. The study, conducted at the U.S. Department of Energy's Brookhaven National Laboratory and published in the May 2012 issue of Alcoholism: Clinical and Experimental Research, now online, provides new evidence that these dopamine receptors, known as DRD2, may play a protective role against alcohol-induced brain damage.

"This study clearly demonstrates the interplay of genetic and environmental factors in determining the damaging effects of alcohol on the brain, and builds upon our previous findings suggesting a protective role of dopamine D2 receptors against alcohol's addictive effects," said study author Foteini Delis, a neuroanatomist with the Behavioral Neuropharmacology and Neuroimaging Lab at Brookhaven, which is funded through the National Institute on Alcohol Abuse and Alcoholism (NIAAA). Coauthor and Brookhaven/NIAA neuroscientist Peter Thanos stated that, "These studies should help us better understand the role of in alcoholism and alcohol-induced brain damage in people, and point the way to more effective prevention and treatment strategies."

The current study specifically explored how affects - overall and region-by-region - in normal mice and a strain of mice that lack the gene for dopamine D2 receptors. Half of each group drank plain water while the other half drank a 20 percent ethanol solution for six months. Then scientists performed (MRI) scans on all the mice and compared the scans of those drinking alcohol with those from the water drinkers in each group.

The scans showed that chronic alcohol drinking induced significant overall and specific shrinkage of the and thalamus in the mice that lacked dopamine D2 receptors, but not in mice with normal receptor levels. Mice in both groups drank the same amount of alcohol.

"This pattern of brain damage mimics a unique aspect of brain pathology observed in human alcoholics, so this research extends the validity of using these mice as a model for studying human alcoholism," Thanos said.

In humans, these are critically important for processing speech, sensory information, and motor signals, and for forming long-term memories. So this research helps explain why alcohol damage can be so widespread and detrimental.

"The fact that only mice that lacked dopamine D2 receptors experienced brain damage in this study suggests that DRD2 may be protective against brain atrophy from chronic alcohol exposure," Thanos said. "Conversely, the findings imply that lower-than-normal levels of DRD2 may make individuals more vulnerable to the damaging effects of alcohol."

That would in effect deal people with low DRD2 levels a double whammy of alcohol vulnerability: Previous studies conducted by Thanos and collaborators suggest that individuals with low DRD2 levels may be more susceptible to alcohol's addictive effects.

"The increased addictive liability and the potentially devastating increased susceptibility to alcohol toxicity resulting from low DRD2 levels make it clear that the dopamine system is an important target for further research in the search for better understanding and treatment of alcoholism," Thanos said.

Explore further: Enzyme might be target for treating smoking, alcoholism at same time

Related Stories

Enzyme might be target for treating smoking, alcoholism at same time

September 12, 2011
An enzyme that appears to play a role in controlling the brain's response to nicotine and alcohol in mice might be a promising target for a drug that simultaneously would treat nicotine addiction and alcohol abuse in people, ...

Receptor limits the rewarding effects of food and cocaine

July 12, 2011
(Medical Xpress) -- Researchers have long known that dopamine, a brain chemical that plays important roles in the control of normal movement, and in pleasure, reward and motivation, also plays a central role in substance ...

Recommended for you

Scientists find RNA with special role in nerve healing process

August 22, 2017
Scientists may have identified a new opening to intervene in the process of healing peripheral nerve damage with the discovery that an "anti-sense" RNA (AS-RNA) is expressed when nerves are injured. Their experiments in mice ...

Mouse model of human immune system inadequate for stem cell studies

August 22, 2017
A type of mouse widely used to assess how the human immune system responds to transplanted stem cells does not reflect what is likely to occur in patients, according to a study by researchers at the Stanford University School ...

Researchers offer new targets for drugs against fatty liver disease and liver cancer

August 22, 2017
There may no silver bullet for treating liver cancer or fatty liver disease, but knowing the right targets will help scientists develop the most effective treatments. Researchers in Sweden have just identified a number of ...

Make way for hemoglobin

August 18, 2017
Every cell in the body, whether skin or muscle or brain, starts out as a generic cell that acquires its unique characteristics after undergoing a process of specialization. Nowhere is this process more dramatic than it is ...

Bio-inspired materials give boost to regenerative medicine

August 18, 2017
What if one day, we could teach our bodies to self-heal like a lizard's tail, and make severe injury or disease no more threatening than a paper cut?

Are stem cells the link between bacteria and cancer?

August 17, 2017
Gastric carcinoma is one of the most common causes of cancer-related deaths, primarily because most patients present at an advanced stage of the disease. The main cause of this cancer is the bacterium Helicobacter pylori, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.