Nicotine’s addictive grip on the brain

Smokers find it enormously difficult to quit: of those who try, only about 10 percent successfully kick the habit each year. The stubbornness of tobacco addiction has been attributed to nicotine, which activates numerous neural networks in the brain by locking onto proteins known as nicotinic acetylcholine receptors, or nAChRs.

Using neuroimaging technology, Julie K. Staley, Ph.D., associate professor of psychiatry and diagnostic radiology, and colleagues compared the number of nAChRs in nonsmokers and in smokers who had abstained from cigarettes for about seven days. As reported in the August 23 issue of The Journal of Neuroscience, the team observed significantly higher densities of nAChRs in the brains of the abstaining smokers than in nonsmokers.

Moreover, the smokers’ urge to light up to relieve withdrawal symptoms was closely related to the number of nAChRs seen in certain brain regions.

“This paves the way for determining why some smokers, such as women and those with neuropsychiatric disorders, have more difficulty quitting,” Staley says.