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!
Climate study finds evidence of global shift in the 1980s
26.11.2015 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Network analysis shows systemic risk in mineral markets
16.11.2015 | International Institute for Applied Systems Analysis (IIASA)
Chemical weathering of rocks over geological time scales is an important control on the stability of the climate. This weathering is, in turn, highly dependent...
Before the fluid of the middle ear drains and sound waves penetrate for the first time, the inner ear cells of newborn rodents practice for their big debut. Researchers at Johns Hopkins report they have figured out the molecular chain of events that enables the cells to make “sounds” on their own, essentially “practicing” their ability to process sounds in the world around them.
The researchers, who describe their experiments in the Dec. 3 edition of the journal Cell, show how hair cells in the inner ear can be activated in the absence...
Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.
Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
01.12.2015 | Event News
30.11.2015 | Event News
25.11.2015 | Event News
01.12.2015 | Life Sciences
01.12.2015 | Life Sciences
01.12.2015 | Earth Sciences