Results of a new imaging study, supported in part by the National Institute on Drug Abuse (NIDA), National Institutes of Health, show that the nicotine received in just a few puffs of a cigarette can exert a force powerful enough to drive an individual to continue smoking. Researchers found that the amount of nicotine contained in just one puff of a cigarette can occupy about 30 percent of the brain's most common type of nicotine receptors, while three puffs of a cigarette can occupy about 70 percent of these receptors. When nearly all of the receptors are occupied (as a result of smoking at least 2 and one-half cigarettes), the smoker becomes satiated, or satisfied, for a time. Soon, however, this level of satiation wears off, driving the smoker to continue smoking throughout the day to satisfy cigarette cravings.
"Imaging studies such as this can add immensely to our understanding of addiction and drug abuse," says Elias A. Zerhouni, M.D., Director of the National Institutes of Health. "These findings suggest that drug therapies or vaccines for smoking cessation need to be extremely potent to compete with nicotine, which binds so readily to these receptors."
The study is published in the August 2006 issue of the Archives of General Psychiatry.
"This study illustrates the powerfully addictive impact of even small amounts of nicotine. Every time a smoker draws a puff from a cigarette, they inhale numerous toxic chemicals that promote the formation of lung cancer, and contribute in a significant way to death and disability worldwide," says NIDA Director Dr. Nora D. Volkow. "Although many smokers endorse a desire to quit, very few are able to do so on their own, and fewer than half are able to quit long-term even with comprehensive treatment. This study helps explain why."
The scientists, led by Dr. Arthur Brody of the David Geffen School of Medicine at UCLA, used positron emission tomography (PET) to scan the brains of 11
Contact: Sara Rosario Wilson
NIH/National Institute on Drug Abuse