Researchers Find Nicotine Affects the Same Brain Areas as Cocaine

Anyone who has ever tried to quit smoking knows how hard it is to do so: only three percent of people who quit stay cigarette-free for a year. A recent study by Medical College of Wisconsin researchers that concluded that nicotine affects the same areas of the brain as cocaine may offer a possible explanation for its addictive properties, and lead to new strategies to help people quit.

The research team, led by Elliot Stein, PhD, Associate Professor of Psychiatry and Behavioral Medicine, used functional magnetic resonance imaging (fMRI) to peer into the recesses of the human brain and create a picture of how nicotine stimulates it.

"Very little is known about how and where addictive drugs act in the human brain," said Dr. Stein. "Our objective was to define those brain systems involved in nicotine and cocaine actions and to determine which of these sites work in withdrawal and craving."

Because smoking is the leading cause of preventable death in the US, better treatment methods based on this information would be very valuable.

The researchers used newspaper ads to recruit a group of healthy smokers, 18 to 39 years old, who smoked about a pack a day.

The research subjects received carefully measured and timed doses of nicotine through intravenous injections while their brains were being imaged using fMRI.

FMRI is a method of observing the brain which allows researchers to "see" activity changes in specific brain areas. Because it is so advanced, the technique allows imaging in very precise locations. MCW is one of the world's leading research centers for fMRI brain studies.

Researchers developed statistical correlation between times, doses, and the subjects' brain activity. The subjects also rated their feelings such as relaxation and stimulation on a scale of 1 to 10.

Researchers found that after the nicotine injections the subjects reported moderate "rushes" or feelings of being "high." Those feelings peaked at two minutes after the injection. The subjects returned to a normal state after five minutes post-injection. At the same time, the fMRI showed increased activity in several areas of the brain including those known to be involved in behavioral arousal, mood, vigilance, attention, and some other cognitive functions. The brain sites affected were the same one shown in other studies to be affected by cocaine use.

The researchers had suspected that brain activation underlies many of the behavioral properties of nicotine - and the fMRI proved them right. Their results were reported in the August 1998 issue of the American Journal of Psychiatry.

Perhaps someday additional research will build on this foundation to find either substances or other methods that can block the action of nicotine on the brain and make it easier for those addicted to the drug to quit smoking.

The study was funded by a $1.5 million grant to MCW from the National Institute on Drug Abuse.

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