Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A genetic difference at the opiate receptor gene affects a person’s response to alcohol

15.12.2004


  • Previous research has implicated the brain’s opioid system in the development of alcohol-use disorders.
  • New findings indicate that individuals with the G variant of the A118 polymorphism of the OPRM1 gene have greater subjective feelings to alcohol’s effects as well as a greater likelihood of a family history of alcohol-use disorders.

Previous research has implicated the brain’s opioid system in the development of alcohol-use disorders. The mu-opioid receptor, which is encoded by the OPRM1 gene, is the primary site of action for opiates with high abuse potential, such as opium and heroin, and may also contribute to the effects of non-opioid drugs, such as cocaine and alcohol. Findings published in the December issue of Alcoholism: Clinical & Experimental Research indicate that individuals with the G variant of the A118 polymorphism of the OPRM1 gene have greater subjective feelings to alcohol’s effects as well as a greater likelihood of a family history of alcohol-use disorders.



"Alcohol releases endogenous opiates which, in turn, seem to influence the mesolimbic dopamine system," said Kent E. Hutchison, associate professor of psychology at the University of Colorado at Boulder and lead author of the study. "This system is involved in craving and the motivation to use alcohol and drugs. Thus, it is alcohol’s effects on endogenous opioids that act as the gateway through which alcohol may influence this system."

"It is well known that alcohol dependence tends to run in families," said Robert Swift, professor of psychiatry and human behavior at Brown University and Associate Chief of Staff for Research at the Providence VA Medical Center. "The inheritance of alcoholism is complex, but there are suggestions that the opiate systems in the brain are involved. Our brains contain proteins, called enkephalins and endorphins, that act like morphine and other opiates derived from the poppy plant. Several researchers have shown that persons with a family history of alcoholism tend to have differences in blood levels of beta-endorphin, a natural opiate hormone, compared to persons without a family history of alcoholism. Children of alcoholics, who are not themselves alcoholics, have lower levels of beta-endorphin than do children of non-alcoholics. Also, when young adults with a family history of alcoholism drink alcohol, they increase their blood levels of beta-endorphin more than those without a family history of alcoholism."


A special protein called the mu-opioid receptor, which is located in the membranes of nerve cells, detects internal opiate neurotransmitters, such as beta-endorphin, that the brain uses to allow nerve cells to communicate with each other. Previous research has shown that the G variant of this gene has a slightly different receptor protein, which causes a big difference in how well the receptor connects with beta-endorphin. For example, the G variant receptor binds three times more tightly than the A variant to beta-endorphin, which means that a nerve cell with the G variant is more greatly affected by beta-endorphin. The net result is that dopamine cells, which play a role in motivation and reinforcement, become more stimulated.

For this study, participants comprised 38 students (20 male, 18 female) at the University of Colorado, 21 to 29 years of age, who indicated drinking patterns classified as moderate to heavy. Participants were either homozygous for the A allele (n=23) or heterozygous (n=15). Each received intravenous doses of alcohol that were designed to cause breath alcohol concentration (BAC) levels of .02, .04, and .06. Researchers measured subjective intoxication, stimulation, sedation, and mood states at baseline and at each of the three BAC levels.

Results indicate that individuals with the G allele had higher subjective feelings of intoxication, stimulation, sedation, and happiness across trials as compared to participants with the A allele.

"The implication is that the trajectory of alcohol dependence may be different among individuals with the G allele," said Hutchison. "If these individuals have a different level of sensitivity, they may also have a differential level of risk for developing alcohol dependence. They may also respond to alcohol treatments differently, especially those that target the mu-opioid receptors, such as naltrexone." Naltrexone treatment is designed to reduce feelings of euphoria after alcohol consumption by blocking beta-endorphin; in fact, a recent study by Dr. David Oslin and colleagues at the University of Pennsylvania suggests that individuals with the G allele may respond better to naltrexone treatment.

The study also found that participants with the G allele were almost three times more likely than those with the A allele to report a family history positive for alcohol-use disorders.

"This manuscript provides further evidence that how one responds to alcohol is inherited," said Swift. "However, it should be noted that the increased risk for alcoholism does not mean that someone with the G allele will necessarily become an alcoholic. The development of alcoholism is only partially determined by heredity. Environmental factors and life experience are as important as heredity."

"These findings add to our expanding knowledge about how genetic factors may influence responses to alcohol and the risk for developing alcohol dependence," said Hutchison. "Given recent growth in our knowledge about the human genome, we will see many more of these kinds of studies in the future." He and his colleagues plan to continue examining the influence of the G variant of the A118 polymorphism of the OPRM1 gene, as well as other genetic variants, on response to alcohol as well as tobacco and marijuana.

"The inheritance of alcoholism is complex," said Swift, "and there are certainly more genes, still undiscovered, that are involved in alcoholism. The search for these genes is an active area of investigation and well worth pursuing. Understanding the genetic basis of the response to alcohol and how it may predict risk for the development of alcoholism could be used as a kind of genetic counseling to help individuals at risk. Persons carrying a risk gene, if they are made aware of it, may be able to alter their drinking and reduce their risk of developing alcoholism."

| EurekAlert!
Further information:
http://www.alcoholism-cer.com
http://www.colorado.edu
http://www.brown.edu

More articles from Health and Medicine:

nachricht UC San Diego researchers develop sensors to detect and measure cancer's ability to spread
06.12.2018 | University of California - San Diego

nachricht New cancer immunotherapy approach turns immune cells into tiny anti-tumor drug factories
05.12.2018 | University of California - San Diego

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

Inaugural "Virtual World Tour" scheduled for december

28.11.2018 | Event News

 
Latest News

A new molecular player involved in T cell activation

07.12.2018 | Life Sciences

High-temperature electronics? That's hot

07.12.2018 | Materials Sciences

Supercomputers without waste heat

07.12.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>