According to the Mammalian Genetics Unit (MRC) and a
consortium or five United Kingdom Universities, a genetic mutation occurring in
the gene Gabrb 1 has been shown to
cause a dysfunction in the regulation of alcohol consumption. Although these
researchers are still working to find whether this faulty gene has the same
affect in humans, they are certain that it has an effect on mice.
When given the choice between alcohol and water, mice
that possess the faulty gene express behaviors of excessive drinking. The
healthy mice showed no interest in the alcohol and were described as drinking little
alcohol to no alcohol. Furthermore, the unhealthy mice have been shown to
consume nearly 85% of their daily liquids via alcohol. These mice were not just
willing to work to acquire the alcohol, but voluntarily working over long
periods of time to consume enough alcohol to become intoxicated.
So what is the science behind this gene? It turns
out that this gene codes for a subunit on the GABAA receptor. We already
know that in humans GABA, an inhibitory neurotransmitter, is essential in
regulating alcohol intake. Researchers have observed that this defect is most significant
in the brain region that controls reward and positive emotions, the nucleus
accumbens. When these receptors are altered due to this defective gene, spontaneous
action potentials occur. When they occur more often in this reward pathway,
researchers observe the mice’s desire for alcohol to significantly increase.
Understanding the mechanisms behind this genetic
mutation in humans will be a scientific breakthrough in examining alcohol
addiction. According to the National Institute of Alcohol Abuse and Alcoholism,
they estimate that around 18 million Americans suffer from an alcohol use
disorder. With this research there is now potential for more effective
treatments, perhaps cures, and even better preventative systems for these
individuals.
The five universities that participated
in this study are Newcastle University, Imperial
College London, Sussex University, University College London and University of
Dundee.
References:
National Institute on Alcohol Abuse and
Alcoholism (NIAAA)
Science Daily - Gene mutation for excessive alcohol drinking found
Interesting find, while there would certainly be strong environmental factors involved in the development of alcoholism it only makes sense that there would be genetic influence involving the physiological pathways of the disorder. There’s also research into other subunits of the GABA receptor, such as subunit Beta-1 which leads to spontaneous activation of the GABA ion channel and increased GABA sensitivity. It all seems to point to up regulation of GABA’s effects increasing alcohol reward. It already appears to be an area of research for treatment, with findings that an allosteric modulator of GABA called gabapentin increased alcohol abstinence and decreased heavy drinking in clinical trials. Genetic risks for alcoholism could lead to preventative measures with proper screening.
ReplyDeleteAnstee QM, Knapp S, Maguire EP, Hosie AM, Thomas P, Mortensen M, Bhome R, Martinez A, Walker SE, Dixon CI, et al. 2013 Nov. Mutations in the gabrb1 gene promote alcohol consumption through increased tonic inhibition. Nat Commun. Available from: http://www.nature.com/ncomms/2013/131126/ncomms3816/full/ncomms3816.html#abstract
Mason BJ, Quello S, Goodell V, Shadan F, Kyle M, Begovic A. 2013 Nov. Gabapentin treatment for alcohol dependence: a randomized clinical trial. JAMA Intern Med. Available from: http://archinte.jamanetwork.com.dml.regis.edu/article.aspx?articleid=1764009
What an interesting proposal that an independent physiological factor such as this gene mutation could result in alcoholism. It makes me think about possible implications for future alcohol treatment; could we one day be taking medicine or other preventive treatments against alcoholism or other substance abuse diseases? I’d be interested to do more research on the exact mechanism this gene mutation has on the receptors you mentioned, and how that is producing these spontaneous action potentials. I remember learning just how sensitive the reward pathway is in the brain and how drugs can severely alter the physiology of these regions, so seeing evidence of this gene acting there makes sense.
ReplyDeleteI agree that it is necessary to take in other environmental factors that play a key role in alcoholism, but, it’s good to see that that research is focusing more on the biological influences on alcoholism, and not just dismissing any sort of substance addiction as solely based on behavior and choice.
I find it interesting that there could be a gene that results in a predisposition towards alcoholism. It certainly lends credence to the concept of alcoholism running in families.
ReplyDeleteThat being said, there is a huge difference between humans and mice, especially when it comes to higher thought processes and brain functioning. Sure, the wiring is essentially the same (we both use neurotransmitters and our brains carry out essentially the same functions) but as humans we are capable of independent thought and higher reasoning. I think it would be wonderful if there was a chemical way that we can help people overcome their alcoholism, but when it comes down to it, without something that also helps people deal with the emotional and psychological reasons why they turned to alcohol in the first place we may just be placing them in a position to enter into an even worse addiction.
Perhaps if/when a genetic or enzymatic treatment is discovered we can also develop a comprehensive counseling program to go along with it. That way we also address the portions of our brains that we don't share with mice.