“Alcoholism is a complex disorder with many contributing factors, one of which is stress. By targeting a particular system that’s associated with stress, we can better understand the interaction of alcohol and stress in the brain.”
~Maureen Cruz, Ph.D., the Scripps Research Institute, first author of Nociceptin/Orphanan and FQ Blockade of CRF-Induced GABA Release in Central Amygdala Is Enhanced after Chronic Ethanol Exposure, published in Biological Psychiatry
A 2011 study by scientists at the Scripps Research Institute has highlighted the particular mechanisms within the brain’s cells that control how a person may go from mere alcohol use to alcohol dependence. Encouragingly, there are indications that this study’s findings could potentially lead to the development of new drugs to treat the disease of alcoholism.
In the study, two opposing peptides were examined. One – corticotropin–releasing factor (CRF) – was a “stress” peptide that has been identified as a key influence in whether an individual transitions from being an alcohol user to an alcohol abuser.
CRF is produced in a part of the brain known as the amygdala, which has been identified as the region that is responsible for the heightened anxiety and heavy drinking linked to alcohol abuse and withdrawal.
“That peptide drives craving for alcohol,” said Associate Professor Marisa Roberto, the second author of the study.
The polar opposite was another peptide –nociceptin – an anti-stress peptide that seems to both prevent and even reverse a number of alcohol’s effects. In laboratory experiments with rats, nociceptin was found to control anxiety levels and the drinking of alcohol.
The two peptides affect the levels of gamma-amino butyric acid (GABA), the neurotransmitter that acts as a natural tranquilizer that inhibits nervous activity. Alcohol mimics the effect of GABA on the brain.
When BOTH peptides are present, nociceptin completely blocks the effects of CRF. But, the news gets even better – as it turns out, nociceptin will counteract CRF and lower GABA levels even after CRF has already had an effect.
“No matter when CRF is added, nociceptin wins. That’s a really consistent effect, “added Professor Roberto.
One key indication from the research was that the peptides had a greater impact on the brains of test rats that were dependent on alcohol, in comparison to those that were not dependent. This increased effect is due to the changes to the brain caused by alcohol dependence. These changes cause a heightened sensitivity to alcohol, which in turn magnifies the effect of drinking and the severity of withdrawal.
This information may point the way to finding another weapon to combat alcoholism. Since there are so many different factors that play a contributing role in the development of the disease – genetics, family history, environment, stress, individual biology – the most promising treatment strategies take a multi-disciplinary approach.
Professor Roberto sums up that philosophy up the best. “Alcohol affects a lot of systems in the brain, and there won’t be a single pill that will cure the multiple and complex aspects of this disease.”