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Study may reveal effective smoking cessation treatments  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 two-and-a-half cigarettes), the smoker becomes 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,” said Elias A. Zerhouni, M.D., director of NIH. “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, published in the August 2006 issue of the Archives of General Psychiatry, illustrates the powerfully addictive impact of even small amounts of nicotine.   The scientists found that the highest levels of nicotine binding occurred in the thalamus (a portion of the brain that acts as a conduit for all sensory information that reaches the brain’s cerebral cortex, and which contains the highest concentration of these nicotine receptors), the brainstem (which controls various automatic functions, such as respiration, heart rate, and arousal), and the cerebellum (the portion of the brain responsible for the coordination of movement and balance). Results of another recently published NIDA-supported study suggest that a portion of the cerebellum called the vermis may be a key factor in modulating the brain’s dopamine and reward systems, and may be more involved in drug abuse and addiction than previously thought.   “The central findings of the study suggest that typical daily smokers need to have these nicotine receptors almost completely saturated throughout the day, which drives the almost uncontrollable urge to keep smoking,” said Nora Volkow, M.D., director of NIDA. “A more complete understanding of how nicotine affects the brain can help us develop better therapies for people looking to quit. In addition, since even low levels of nicotine exposure result in substantial occupancy of these receptors, additional research needs to address the impact of secondhand, or environmental, tobacco smoke on nicotine craving.”   Beginning in the fall MUSC will implement a smoke-free campus policy.  Free smoke cessation clinics are available. Information about MUSC programs can be found at http://www.musc.edu/asap, or call 792-2388.   In addition, one member of this group directs a weekly smoking cessation meeting in the Department of Psychiatry (call 792-1414 for details).   Another resource is the State of South Carolina quit line for information and support on smoking cessation (877-448-7848).     Friday, Aug. 11, 2006 Catalyst Online is published weekly, updated as needed and improved from time to time by the MUSC Office of Public Relations for the faculty, employees and students of the Medical University of South Carolina. Catalyst Online editor, Kim Draughn, can be reached at 792-4107 or by email, catalyst@musc.edu. Editorial copy can be submitted to Catalyst Online and to The Catalyst in print by fax, 792-6723, or by email to catalyst@musc.edu. To place an ad in The Catalyst hardcopy, call Island Publications at 849-1778, ext. 201.