November 16, 2004

Scientists approach addiction source

California researchers have isolated a brain cell receptor that plays a key role in nicotine addiction, a significant finding for the 57 percent of University of Chicago smokers who, according to the 2004 statistics from the Student Health Assessment Survey, simply want to quit.

Researchers at the California Institute of Technology used genetic manipulations to demonstrate the addictive effects of a mutation in a subunit of a nicotinic acetylcholine receptor. When this receptor, designated as alpha4, was expressed in mice, the animals showed a greater sensitivity to nicotine. The mice were affected by concentrations of nicotine normally too low to have an effect on the animals.

Prior to the study, 12 brain cell receptors were known to be nicotine-activated. It was not known, however, that any one receptor was primarily responsible for nicotine addiction.

This finding has clear import for smokers who are trying to kick the habit. Developing a drug to block the alpha4 subunit would reduce smokers' sensitivity to nicotine and make it easier to quit. But researchers are not yet sure what side effects such a drug might have.

"These receptors likely play important roles in the brain circuitry that reinforces healthy behavior like eating and drinking and studying," said Dr. Daniel McGehee, who has worked on nicotinic receptor function since 1991 and is currently an assistant professor in the Department of Anesthesiology at the University of Chicago. "It is possible that blocking those receptors would alter the way we experience these healthy behaviors."

In the 2004 Student Health Assessment Survey, 71 percent of students reported that they had not smoked cigarettes in the past year. Of the students who identified themselves as smokers, 15-20 percent consider themselves "light" or "infrequent" smokers. The national onset age of tobacco use is 16-17 years. 32 percent of Chicago students who smoke said they began the habit between 18-20 years of age.

Kelley Carameli, health education specialist at the Student Care Center (SCC), attributed these numbers, which fall below the national averages, to the importance students place on leading healthy lifestyles. "U of C students are great at researching and inquiring about their health," she said. "They look at the research and make conscious decisions as to their own risks and benefits."

Carameli said she finds that many of the students who do smoke plan to quit. "Unfortunately, when it comes to tobacco, students often assume that their use will be temporary to relieve stress, etcetera, but it eventually turns into an addiction that they find hard to fight and ‘put off' until graduation, which only makes quitting harder."

Many smokers, in an attempt to cut back, switch to cigarettes that are marketed as "light" or "mild." In a 2002 study, researchers at Health Canada found that two of every three smokers of "light" cigarettes made the switch to light cigarettes because they believed they would suffer fewer health risks. 90 percent of the cigarettes sold in the United States are marketed as ‘light' according to the Associated Press.

On March 21, 2003 an Illinois judge found Philip Morris's marketing of light cigarettes to be in violation of the state's Consumer Fraud and Deceptive Business Practices Act, and ordered the company to pay $10 billion in damages. A class-action lawsuit against the company was initiated in August 2004. The plaintiffs claim that the company fraudulently marketed Marlboro Lights as less harmful than other brands.

At a time when the price of a pack of cigarettes creeps ever higher, the past decade has shown a national rise in teenage smoking. The National Bureau of Economic Research (NBER) reported that, unlike adult smoking, youth smoking is not concentrated in lower socioeconomic groups and is relatively unaffected by increased cigarette prices.

This increase is especially dramatic among teenage girls, according to the NBER despite the fact that lung cancer has risen to the leading cause of cancer death in women.

The SCC offers free smoking cessation workshops and meets with students seeking a prescription for Zyban as a cessation method. The SCC is also sponsoring the national Great American SmokeOut campaign, which comes to Chicago's campus on November 18.