PNAS: PET yields insight into nicotine addiction
A study using PET imaging to compare nicotine accumulation in smokers found that nicotine washed out of the addicted smoker’s lungs and into their blood less efficiently and the study could help provide a treatment program for cigarette smokers who are trying to quit, according to a research scheduled to appear online in the early edition of Proceedings of the National Academy of Sciences during the week of March 8.

Jed E. Rose, PhD, director for the Center for Nicotine and Smoking Cessation Research at Duke University Medical Center in Durham, N.C., and colleagues investigated the dynamics of nicotine accumulation in the smoker’s brain during actual cigarette smoking using PET with 11C-nicotine loaded into cigarettes in 13 dependent smokers and 10 nondependent smokers.

Two of the popular hypotheses to explain the development and maintenance of strong nicotine dependence in cigarette smokers are a rapid brain nicotine accumulation during cigarette smoking and/or puff-associated spikes in brain nicotine concentration, wrote Rose and colleagues.

The investigators found that puff-associated spikes in brain nicotine concentration did not exist during usual habitual cigarette smoking. Brain nicotine concentration steadily increased during cigarette smoking, producing only “a single spike” in brain nicotine associated with smoking of an entire cigarette, according to Rose and colleagues.

“Dependent smokers have a slower process of brain nicotine accumulation than nondependent smokers because they have slower nicotine washout from the lungs,” wrote Rose and colleagues. Dependent smokers have a tendency to compensate for their slower rate of brain nicotine accumulation compared with nondependent smokers by inhaling a larger volume of smoke, added the authors.

However, Rose and colleagues noted that, even without discrete puff-associated spikes, the rapid brain accumulation of nicotine, which starts at approximately seven seconds after inhalation, may be a factor leading to the relatively high addictiveness of cigarettes relative to other forms of nicotine administration (e.g., nicotine patch).

“The study could help provide a treatment program for cigarette smokers who are trying to quit,” concluded the authors.