Alcohol-Induced Brain Shrinkage Linked to Genetic Vulnerability

August 7, 2012 § Leave a comment

A study to be published in the May 2012 issue of Alcoholism: Clinical and Experimental Research revealed that dopamine receptors DRD2 might perform a protective role against brain damage resulting from alcohol consumption. The study was conducted at the U.S. Department of Energy’s Brookhaven National Laboratory.

The research team issued significant volumes of alcohol to two different strains of mice. They then performed brain scans to observe for changes in brain size and functioning. The brain scans revealed significant shrinkage in certain critical brain regions in the mice that were lacking a certain dopamine receptor, DRD2. Dopamine is the brain’s “reward” chemical. This neurotransmitter is also responsible for the formation of new neurons in the adult brain.

This study explored how alcohol consumption affects brain volume in the two strains of mice. A control group was formed by splitting each strain of mice in half. Those in the control group were given plain water instead of alcohol. The two experimental groups were both given a 20% ethanol solution. After 6 months of this treatment, scientists performed MRI scans on all the mice and compared the four groups.

The scans revealed that consumption of alcohol generated considerable brain atrophy, with shrinkage occurring specifically in the cerebral cortex and thalamus of the mice that lacked the DRD2 receptors. In the mice with the normal receptor levels, significant shrinkage did not occur.

Study author, Foteini Delis, neuroanatomist at the Behavioral Neuropharmacology and Neuroimaging Lab at Brookhaven, said, “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.” Coauthor Peter Thanos, neuroscientist at Brookhaven NIAAA, stated, “These studies should help us better understand the role of genetic variability in alcoholism and alcohol-induced brain damage in people, and point the way to more effective prevention and treatment strategies.”

Thanos claims that the use of mice as a model is valid because the same pattern of brain damage is found in the brain pathology of human alcoholics. In humans, these shrunken brain regions are responsible for processing speech, sensation, motor signals, and for the formation of long-term memory. Thanos says, “DRD2 may be protective against brain atrophy from chronic alcohol exposure … the findings imply that lower-than-normal levels of DRD2 may make individuals more vulnerable to the damaging effects of alcohol.” This means that those with low DRD2 levels are much more susceptible to the addictive and damaging effects of alcohol.

The findings of this study indicate that future research geared toward the understanding and treatment of alcoholism must target the dopamine system.

 

 

Works Cited

“Dopamine Controls Formation of New Brain Cells”. (April 8, 2011). Neuroscience News. February 19, 2012. http://neurosciencenews.com/dopamine-controls-formation-brain-cells-neurons/.

“Drinking Alcohol Shrinks Critical Brain Regions in Genetically Vulnerable Mice”. (February 15, 2012). Neuroscience News. February 19, 2012. http://neurosciencenews.com/drinking-alcohol-shrinks-brain-regions-genetics-mice-drd2/.

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