University of Utah neuroscientists finds the lateral habenula controls sensitivity to the negative effects of drinking alcohol
As recovering spring breakers are regretting binge drinking escapades, it may be hard for them to appreciate that there is a positive side to the nausea, sleepiness, and stumbling.
University of Utah neuroscientists report that when a region of the brain called the lateral habenula is chronically inactivated in rats, they repeatedly drink to excess and are less able to learn from the experience. The study, published online in PLOS ONE on April 2, has implications for understanding behaviors that drive alcohol addiction.
While complex societal pressures contribute to alcoholism, physiological factors are also to blame. Alcohol is a drug of abuse, earning its status because it tickles the reward system in the brain, triggering the release of feel-good neurotransmitters. The dreaded outcomes of overindulging serve the beneficial purpose of countering the pull of temptation, but little is understood about how those mechanisms are controlled.
U of U professor of neurobiology and anatomy Sharif Taha, Ph.D. and colleagues, tipped the balance that reigns in addictive behaviors by inactivating in rats a brain region called the lateral habenula. When the rats were given intermittent access to a solution of 20% alcohol over several weeks, they escalated their alcohol drinking more rapidly, and drank more heavily than control rats.
"In people, escalation of intake is what eventually separates a social drinker from someone who becomes an alcoholic," said Taha. "These rats drink amounts that are quite substantial. Legally they would be drunk if they were driving,"
The lateral habenula is activated by bad experiences, suggesting that without this region the rats may drink more because they fail to learn from the negative outcomes of overindulging. The investigators tested the idea by giving the rats a desirable, sweet juice then injecting them with a dose of alcohol large enough to cause negative effects.
"It's the same kind of learning that mediates your response in food poisoning. You taste something and then you get sick, and then of course you avoid that food in future meals," explained Taha.
Yet rats with an inactivated lateral habenula sought out the juice more than control animals, even though it meant a repeat of the bad experience.
"The way I look at it is the rewarding effects of drinking alcohol compete with the aversive effects," explained Andrew Haack, who is co-first author on the study with Chandni Sheth, both neuroscience graduate students. "When you take the aversive effects away, which is what we did when we inactivated the lateral habenula, the rewarding effects gain more purchase, and so it drives up drinking behavior."
The group's findings may help explain results from previous clinical investigations demonstrating that men who were less sensitive to the negative effects of alcohol drank more heavily, and were more likely to become problem drinkers later in life.
The researches think the lateral habenula likely works in one of two ways. The region may regulate how badly an individual feels after over-drinking. Alternatively, it may control how well an individual learns from their bad experience. Future work will resolve between the two.
"If we can understand the brain circuits that control sensitivity to alcohol's aversive effects, then we can start to get a handle on who may become a problem drinker," said Taha.
Listen to an interview with Sharif Taha on The Scope Radio
Read the article in PLOS ONE
Funding support was provided by the National Institutes Health under award MH094870, the March of Dimes Foundation, and the University of Utah.
Julie Kiefer | EurekAlert!
Is Marriage Good or Bad for the Figure?
29.06.2015 | Max-Planck-Institut für Bildungsforschung
Fructose produces less rewarding sensations in the brain
25.06.2015 | Universität Basel
Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and a half billion years ago.
Think of an object made of iron: An I-beam, a car frame, a nail. Now imagine that half of the iron in that object owes its existence to bacteria living two and...
A team of scientists including PhD student Friedrich Schuler from the Laboratory of MEMS Applications at the Department of Microsystems Engineering (IMTEK) of...
The three-year clinical trial results of the retinal implant popularly known as the "bionic eye," have proven the long-term efficacy, safety and reliability of...
On June 23, the second Sentinel mission was launched from the space mission launch center in Kourou. A critical component of Aachen is on board. Researchers at the Fraunhofer Institute for Laser Technology ILT and Tesat-Spacecom have jointly developed the know-how for space-qualified laser components. For the Sentinel mission the diode laser pump module of the Laser Communication Terminal LCT was planned and constructed in Aachen in cooperation with the manufacturer of the LCT, Tesat-Spacecom, and the Ferdinand Braun Institute.
After eight years of preparation, in the early morning of June 23 the time had come: in Kourou in French Guiana, the European Space Agency launched the...
(Nano)islands that slide freely on a sea of copper, but when they become too large (and too dense) they end up getting stuck: that nicely sums up the system...
25.06.2015 | Event News
16.06.2015 | Event News
11.06.2015 | Event News
30.06.2015 | Life Sciences
30.06.2015 | Earth Sciences
30.06.2015 | Materials Sciences