Smoking Therapy (03.29.05) - Psychologists have shown that for some, giving up for good may require long-term counseling as well as medication. Smoking Damage (06.21.04) - New research reveals how smoking causes some damage to your DNA that you can't undo. Health Effects of Smoking Among Young People The Irreversible Effects of Cigarette Smoking We know smoking can damage lungs. But new research shows it may also impact how a key body chemical passes along substances like nicotine. The finding may explain why some smoke more, and could provide new treatment for smokers bent on quitting. This ScienCentral News video has more. The Inner Workings of Smoking There's probably not a smoker out there who won't tell you the same thing: Don't try it. That's because despite years of repeated messages in public service campaigns — smoking is a health risk — many who start find it hard to stop. A new study that uses PET scanning and a tracer chemical that binds to an enzyme, called monamine oxidase (MAO), is helping researchers track MAO in smokers and non-smokers. The findings may explain why smokers ramp up their cigarette intake over time and could offer a new tool for those struggling to quit. The enzyme is crucial to blood pressure and mood regulation and has two subtypes — MAO A and B. Initially Fowler tracked only MAO B. As reported in Discover Magazine , that study showed that levels of MAO B in smokers' peripheral organs — the heart, kidneys, spleen and lungs — were reduced by 40 to 50 percent compared to non-smokers. "But we do not think that... the degree to which monoamine oxidase is inhibited in peripheral organs will be detrimental to the smoker," says Fowler. So, if reduced MAO doesn't necessarily hurt smokers' organs, no big deal, right? Not so fast. Fowler's latest study traced MAO A in the bodies of nine smokers and nine non-smokers. She found that in smokers, "[MAO] A is fairly well intact in all of the organs but the lungs." There, she saw levels in smokers that were 50 percent lower than in non-smokers, and she also saw that smokers held onto the tracer much longer than non-smokers, suggesting lower blood concentration in smokers' lungs. She explains: "It means, for example… that your lungs are going to retain nicotine, that you're going to have a lower level of nicotine in your bloodstream than say a non-smoker, someone just starting out smoking." Controlling MAO might help smokers quit. "We may be able to develop better treatments," says Fowler. "I know now people are actually trying monoamine oxidase inhibitors for smoking cessation, reasonably successfully. So as we learn the effects on the brain, we will learn more about what happens when you withdraw a cigarette from an individual, for example. Are they missing their nicotine? Yes, they're missing their nicotine, but they may also be missing their monoamine oxidase inhibitor. So that rationale is one may need to prop both of those things up in treatment." One may want to keep in mind, however, that these drugs can have drastic side effects. "We can go back to studies, the early studies with monoamine oxidase inhibitor drugs, which were used to treat depression and there were very serious toxic effects from those because, when people were taking monoamine oxidase inhibitor drugs, food that had high levels of substances that caused surges in blood pressure, might have a toxic blood pressure surge," she says. "In fact, deaths occurred, and still occur with monoamine oxidase inhibitors when you don't follow very strict instructions." No matter how smokers choose to confront their habit, there probably won't be a one-size fixes all solution to finally tossing the cigarettes you tuck away for the daily grind. "The effects of smoking on the body are really complicated," Fowler reminds us. "We need to learn a lot more about it to know what's really going on." Fowler's research was published in the September, 2005 issue of The Journal of Nuclear Medicine , and was funded by the U.S. Department of Energy Office of Biological and Environmental Research , and the Nati

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