Brain chemistry ties anxiety and alcoholism

Mar 04, 2008

Doctors may one day be able to control alcohol addiction by manipulating the molecular events in the brain that underlie anxiety associated with alcohol withdrawal, researchers at the University of Illinois at Chicago College of Medicine and the Jesse Brown VA Medical Center report in the March 5 issue of the Journal of Neuroscience.

"The association of anxiety with increased alcohol use is a key factor in the initiation and maintenance of alcohol addition," says Dr. Subhash Pandey, UIC professor of psychiatry and director of neuroscience alcoholism research, the lead author of the study.

Previous research has shown that people with inherently high levels of anxiety are at an increased risk of becoming alcoholics. In addition, withdrawal of alcohol in chronic users is often accompanied by extreme anxiety.

"Alcoholics may feel a need to continue to drink alcohol in an attempt to self-medicate to reduce their anxiety and other unpleasant withdrawal symptoms," said Pandey.

Pandey and his colleagues have discovered the molecular basis for the link between anxiety and alcohol addiction, which may help in identifying new therapeutic strategies for the treatment of alcohol addiction.

The researchers found that a protein within neurons in the amygdala -- the area of the brain associated with emotion and anxiety -- controls the development of alcohol withdrawal symptoms and drinking behaviors in laboratory animals by changing the shape of the neurons. This change in shape affects the communication between neurons, leading to changes in behavior.

Neurons communicate by sending signals through branches called dendritic spines. The researchers found that short-term alcohol exposure increased the number of dendritic spines in certain regions of the amygdala, producing anti-anxiety effects. Alcohol-dependent animals eventually developed a tolerance to the anxiety-lowering effects of alcohol.

The researchers traced the anti-anxiety effect to the production of a particular protein, Arc, in response to a nerve growth factor called BDNF that is stimulated by alcohol exposure. BDNF is vital in the functioning and maintenance of neurons.

When alcohol was withheld from animals that had been chronically exposed, they developed high anxiety. Levels of BDNF and Arc -- and the number of dendritic spines -- were decreased in the amygdala. But the researchers were able to eliminate the anxiety in the alcohol-dependent animals by restoring BDNF and Arc to normal levels.

Pandey suggested that an initial easing of anxiety may encourage people to begin to use alcohol, while for chronic users, a lack of alcohol provokes high anxiety, creating a need to continue drinking to feel normal.

The researchers blocked Arc production in normal rats by injecting a complementary sequence to Arc gene DNA into the central amygdala. They found that when levels of Arc in the central amygdala were lowered, the spines decreased and anxiety and alcohol consumption increased. When levels of Arc were returned to normal three days post-injection, anxiety and alcohol consumption also returned to normal. In a previous study, researchers found that lowering BDNF in amygdala promoted anxiety and alcohol drinking.

"This is the first direct evidence of the molecular processes occurring in the neurons that is responsible for the co-morbidity of anxiety and alcoholism, which we believe plays a major role in the addictive nature of alcohol," said Pandey.

"This offers the possibility of new therapeutic target -- BDNF-Arc signaling and associated dendritic spines in the amygdala -- or new drug development."

"These observations by Dr. Pandey's research group provide an insight into the link between alcohol and anxiety and could be used to identify new targets for developing medications that alleviate withdrawal-induced anxiety and potentially modify a motivation for drinking," said Antonio Noronha, director of neuroscience and behavior research at the National Institute on Alcohol Abuse and Alcoholism.

Source: University of Illinois at Chicago

Explore further: Researchers developing an artificial vision system for prosthetic legs to improve gait

add to favorites email to friend print save as pdf

Related Stories

Korean tech start-ups offer life beyond Samsung

2 hours ago

As an engineering major at Seoul's Yonsei University, Yoon Ja-Young was perfectly poised to follow the secure, lucrative and socially prized career path long-favoured by South Korea's elite graduates.

Fresh nuclear leak detected at Fukushima plant

14 hours ago

Sensors at the Fukushima nuclear plant have detected a fresh leak of highly radioactive water to the sea, the plant's operator announced Sunday, highlighting difficulties in decommissioning the crippled plant.

Spacewalking astronauts route cable in 1st of 3 jobs

15 hours ago

(AP)—Spacewalking astronauts routed more than 300 feet (90 meters) of cable outside the International Space Station on Saturday, tricky and tiring advance work for the arrival of new American-made crew ...

Recommended for you

Many transplant surgeons suffer burnout

Feb 25, 2015

Despite saving thousands of lives yearly, nearly half of organ transplant surgeons report a low sense of personal accomplishment and 40% feel emotionally exhausted, according to a national study on transplant surgeon burnout

5 tips for handling early-year medical expenses

Feb 25, 2015

The clock on insurance deductibles reset on Jan. 1, and that means big medical bills are in store for some. Patients may be required to pay thousands of dollars before their health care coverage kicks in.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.