-----Original Message-----
From: NIH news releases and news items [mailto:[log in to unmask]] On
Behalf Of NIH OLIB (NIH/OD)
Sent: Tuesday, May 18, 2010 9:58 AM
To: [log in to unmask]
Subject: RECEPTOR VARIANT INFLUENCES DOPAMINE RESPONSE TO ALCOHOL
U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH NIH News
National Institute on Alcohol Abuse and Alcoholism
(NIAAA)<http://www.niaaa.nih.gov/>
Embargoed for Release: Tuesday, May 18, 2010, 9 a.m., EDT
CONTACT: NIAAA Press Office,301-443-3860, <e-mail:
[log in to unmask]>
RECEPTOR VARIANT INFLUENCES DOPAMINE RESPONSE TO ALCOHOL
A genetic variant of a receptor in the brain's reward circuitry plays an
important role in determining whether the neurotransmitter dopamine is
released in the brain following alcohol intake, according to a study led by
researchers at the National Institute on Alcohol Abuse and Alcoholism
(NIAAA), part of the National Institutes of Health. Dopamine is involved in
transmitting the euphoria and other positive subjective effects produced by
alcohol.
A report of the findings, which help explain the diverse genetic
susceptibility for alcohol use disorders, will appear online in Molecular
Psychiatry on May 18, 2010.
"By advancing our understanding of the neurobiology that underlies the
addictive properties of alcohol, this finding helps us understand why
alcohol affects people in very different ways," says NIAAA Acting Director
Kenneth R. Warren, Ph.D. "This kind of information also aids the development
of personalized medications for alcohol problems."
Receptors for brain molecules known as opioid peptides help initiate the
neurochemical reactions that underlie the positive effects produced by
alcohol. Activation of the mu-subtype of opioid receptor following alcohol
consumption triggers the release of dopamine from the forebrain.
"But there is much variation in alcohol-induced responses that are thought
to be related to dopamine," explains Markus Heilig, M.D., Ph.D., NIAAA
clinical director and the study's senior author. "Previous studies by our
group and others suggest that variants of opioid genes may contribute to the
observed variation, possibly through effects on alcohol-induced dopamine
release."
He notes, for example, that people who carry the mu-opioid receptor variant
designated as 118G report increased euphoria following alcohol consumption.
Dr. Heilig's group has reported that a similar mu-opioid receptor variant in
monkeys heightened the stimulating effects of alcohol and increased their
alcohol consumption.
In the current study, first author Vijay A. Ramchandani, Ph.D., an
investigator in NIAAA's Laboratory of Clinical and Translational Studies,
Dr. Heilig, and their colleagues explored whether the 118G mu-opioid
receptor variant influences dopamine release from a forebrain region called
the ventral striatum in response to alcohol.
Using human positron emission tomography (PET), an imaging technique that
allowed the researchers to analyze dopamine activity in the brain, they
compared dopamine release in two groups of people that had been given a dose
of alcohol. The groups consisted of those who carried a copy of the gene for
the 118G mu-opioid receptor variant, and those who carried only genes for
the more common 118A variant. They found that only people with the 118G
variant had a dopamine response to alcohol - no such response happened in
subjects with the 118A receptor variant.
In a separate experiment, they inserted genes for the human 118G or 118A
mu-opioid receptor variants into mice and then directly measured the
animals' dopamine response to a dose of alcohol. Mice with the 118G variant
showed a fourfold higher peak dopamine response to the alcohol challenge
compared to mice with the 118A variant.
"Taken together, our data strongly support a causal role of the 118G variant
of the mu-opioid receptor to confer a more vigorous dopamine response to
alcohol in the ventral striatum," says Dr. Ramchandani. "The findings add
further support to the notion that individuals who possess this receptor
variant may experience enhanced pleasurable effects from alcohol that could
increase their risk for developing alcohol abuse and dependence. It may also
explain why these individuals, once addicted, benefit more from treatment
with blockers of endogenous opioids."
The National Institute on Alcohol Abuse and Alcoholism, part of the National
Institutes of Health, is the primary U.S. agency for conducting and
supporting research on the causes, consequences, prevention, and treatment
of alcohol abuse, alcoholism, and alcohol problems. NIAAA also disseminates
research findings to general, professional, and academic audiences.
Additional alcohol research information and publications are available at
<www.niaaa.nih.gov>.
The National Institutes of Health (NIH) -- The Nation's Medical Research
Agency -- includes 27 Institutes and Centers and is a component of the U.S.
Department of Health and Human Services. It is the primary federal agency
for conducting and supporting basic, clinical and translational medical
research, and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and its programs,
visit <www.nih.gov>.
--------------
ADDITIONAL INFORMATION
Why Meds Work for Some People, but Not for Others
(http://nihrecord.od.nih.gov/newsletters/2010/05_14_2010/story2.htm)
NIH Record, 5/14/2010
Alcohol's effects on endogenous opioids in the brain
(http://www.niaaa.nih.gov/Resources/GraphicsGallery/Neuroscience/31_4_endoge
nous.htm)
##
This NIH News Release is available online at:
<http://www.nih.gov/news/health/may2010/niaaa-18.htm>.
To subscribe (or unsubscribe) from this list, go to
<http://service.govdelivery.com/service/subscribe.html?code=USNIH_1>.
__________ Information from ESET NOD32 Antivirus, version of virus signature
database 5124 (20100518) __________
The message was checked by ESET NOD32 Antivirus.
http://www.eset.com
__________ Information from ESET NOD32 Antivirus, version of virus signature
database 5124 (20100518) __________
The message was checked by ESET NOD32 Antivirus.
http://www.eset.com
-----------------------
To change your mail settings or leave the C-PALSY list, go here:
http://listserv.icors.org/SCRIPTS/WA-ICORS.EXE?SUBED1=c-palsy
|
