Brain Nicotine Levels Gradually Increase to One Spike, Not Many

Two popular hypotheses have been used to explain the addictive nature of nicotine in cigarette smokers: 1) a rapid brain nicotine accumulation during smoking and/or 2) puff-associated spikes in brain nicotine concentration.  Researchers from Duke University Medical Center and Wake Forest University School of Medicine set out to address these hypotheses by investigating the dynamics of nicotine accumulation in a smoker’s brain during actual cigarette smoking using positron emission tomography (PET) with 3-s temporal resolution and C-nicotine loaded cigarettes.  Published online yesterday in the Early Edition of Proceedings of the National Academy of Sciences, the results of the study suggest that puff-associated spikes in brain nicotine concentration do not and could not exist during habitual cigarette smoking.  Brain nicotine concentration steadily increases during smoking, producing one spike in brain nicotine associated with smoking of an entire cigarette.  Furthermore, dependent smokers have a slower process of brain nicotine accumulation than nondependent smokers because they have slower nicotine washout from the lungs.  For this reason, researcher said, more rapid brain nicotine accumulation alone is not sufficient to maintain a dependency on cigarette smoking.

Researchers noted that even without discrete puff-associated spikes, the rapid brain accumulation of nicotine (which starts about seven seconds after inhalation), may be a factor leading to the relatively high addictiveness of cigarettes when compared to other forms of nicotine administration such as nicotine patches and gum.  Because understanding the mechanisms that underlie nicotine dependence in cigarette smokers is crucial to developing improved strategies to help with smoking cessation, it is important that further research is done to unveil the specific role of the rate of brain nicotine accumulation in controlling smoking behavior.

Brandi Robinson

Program Associate, Partnership for Prevention

Sorry, But Size Matters...

E-cigarette manufacturers and proponents are touting the results of a recent study that suggests e-cigs have better effects on the human heart rate than regular cigarettes. But the study only looked at 16 people, and was conducted by a Virginia Commonwealth University professor with long-standing ties to the tobacco industry.

Nicotine Vaccine May Help Prevent Smoking Addiction, Relapse

Twenty-two institutions across the country are participating in a Phase III clinical trial to determine whether a new investigational "nicotine vaccine" is safe, effective and capable of stimulating an immune response. Approximately 1,000 male and female smokers aged 18 to 65 will take part in the 12-month study NicVAX, a vaccine developed by Nabi Biopharmaceuticals.

Nicotine molecules are so small that they can pass through the body's brain/blood barrier without triggering a reaction from the immune system. However, NicVAX stimulates the immune system to produce antibodies that bind to or capture nicotine
molecules in the bloodstream, making them too large to cross the blood-brain barrier. As a result, many of the expected rewards from smoking are blocked, making it easier for the smoker to become and remain abstinent.

“Smokers continue to smoke even when they know it’s harmful because of these ‘brain effects,’” explained David Gonzales, Ph.D., principal investigator and clinical investigator in medicine at the Oregon Health and Science University, one of the 22 test centers. “While a smoking cessation medication such as varenicline prevents nicotine from binding to receptors once it is in the brain, NicVAX is designed to block nicotine before it enters the brain.”

FDA Can't Regulate E-Cigarettes, Court Rules; AG Files Separate Suit in CA

U.S. District Judge Richard Leon today ruled that the U.S. Food and Drug Administration may not regulate electronic cigarettes as drugs or medical devices.

"This case appears to be yet another example of FDA's aggressive efforts to regulate recreational tobacco products as drugs or devices," Judge Leon said in his ruling. He added the FDA's "tenacious drive to maximize its regulatory power has resulted in its advocacy of an interpretation of the relevant law that I find, at first blush, to be unreasonable and unacceptable."

The FDA has seized shipments of e-cigarettes, saying the electronic cigarettes were essentially drugs or devices that were being imported without FDA approval.

Meanwhile, California Attorney General Jerry Brown has filed suit seeking to halt the sale of one company's electronic cigarettes in the state, saying they contain dangerous chemicals and are being marketed to children.
Brown says Florida-based Smoking Everywhere Inc., a leading manufacturer of e-cigarettes, has no evidence to back up claims their product is safe.

Researchers to Study Nicotine Vaccine for Smokers

USA TODAY's Rita Rubin reports that researchers are investigating whether the same approach used to prevent infectious diseases could treat addictions to such drugs as nicotine.

Nabi Pharmaceuticals has gotten a $10-million grant to study the effectiveness and to monitor the side effects of a smoking-cessation vaccine. Nabi, based in Rockville, Md., expects to begin enrolling patients in the NicVax study by year's end.

Don't Give E-Cigs a Pass

USA Today ran a front page story on Oct. 26 detailing the growing controversy posed by electronic cigarettes. Proponents claim the cigarette alternative is safe and shouldn’t be regulated. Public health officials want the Food and Drug Administration (FDA) with its new authority over tobacco products, to test and regulate e-cigarettes. Electronic cigarettes are battery-operated devices that turn nicotine and other chemicals into a vapor inhaled by the user. The smokers’ argument is “no smoke, no problem.” Not so easy say others. Potential dangers not known, so we can’t give it a pass.

Diane Canova Managing Senior Fellow
& Senior Program Officer
Partnership for Prevention