HealthDayNews
-- Even low levels of alcohol can impair brain function, says
a study that found the specific areas affected by amounts
of alcohol tantamount to social drinking.
Low levels of alcohol affect motor coordination, memory and
lower social inhibitions at a blood alcohol level of 0.01
percent, far below the legal drinking and driving limit of
0.08 percent, says lead researcher Dr. Richard Olsen, a professor
of pharmacology at the University of California at Los Angeles.
"This is the effect one or two drinks will have," he adds.
In experiments with gamma aminobutyric acid (GABA) receptors
in animal cells, Olsen and his colleagues found some receptors,
namely GABA receptors with a beta-3 subunit and a delta subunit,
responded when exposed to low levels of ethanol.
These GABA receptors responded to low levels of alcohol compared
with other GABA receptors with subunits, such as gamma-2,
that respond to much higher levels, far higher than achieved
in social drinking, Olsen says.
The GABA receptors that respond to low levels of alcohol are
in cellular areas and brain regions that control the effects
of alcohol on behavior, he notes.
These areas include the cerebellum, which controls motor coordination,
the hippocampal formation, which affects memory loss, and
the thalamus, which is involved with sleep and effects of
anesthetics.
The report appears in this week's issue of the Proceedings
of the National Academy of Sciences (news - web sites).
Olsen says some of these receptors have not been tested for
reaction to alcohol before. These receptors are also being
looked at to see the effects of anesthetics.
This finding is useful because researchers may be able to
effect the action of alcohol if they know exactly how it works
at the molecular and cellular level on GABA receptors, he
adds.
It is possible the changes that occur in the brain after chronic
abuse of alcohol can involve changes in these receptors, and
this may help scientists understand alcohol dependence and
abuse. Researchers have some evidence that GABA receptors
are indeed modified by continued exposure to alcohol, Olsen
notes.
Currently, Olsen's team is taking the next step by trying
to duplicate their findings in rats.
"If we understand the action of alcohol at the cellular and
molecular level, it is helpful in treating the bad effects
that alcohol may have," Olsen says.
"We may be able to develop antidotes or treatments for intoxication
or overdoses and coma and life-threatening effects as well
as being able to understand and treat alcohol abuse," he adds.
Dr. H. Scott Swartzwelder, a professor psychiatry of at Duke
University, comments, "We have always known that alcohol has
some kind of effect on GABA function, because GABA is involved
in learning and sleep."
The results of this study are compelling because it shows
concentrations that are relevant to the human experience,
and there may be a specific target that will let researchers
study the effects of alcohol, Swartzwelder adds.
"This is important because alcohol is a very dirty drug: it
doesn't just do one thing; it affects many types of receptors
in the brain," he says. "This finding could lead to the development
of drugs that could block or reverse some of the effects of
alcohol."
"We have hoped for a long time to find a drug that would counteract
the acute effects of alcohol and also the chronic effects
of alcohol. Chronic alcohol use does change the ways the GABA
system works, and it stays changed. Knowing how alcohol affects
the GABA system may lead to drugs that can reverse these changes,"
Swartzwelder speculates.
HealthDayNews
-- Even low levels of alcohol can impair brain function, says
a study that found the specific areas affected by amounts
of alcohol tantamount to social drinking.
