http___metro-portal.hr_otkriveno-zasto-se-zene-tesko-ostavljaju-cigareta_69753_1.xml
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Women tend to find it harder to quit smoking than men, and a new study suggests why — women's brains respond differently to nicotine, the researchers say. When a person smokes, the number of nicotine receptors in the brain — which bind to nicotine and reinforce the habit of smoking — are thought to increase in number. The study found in men, this is true — male smokers had a greater number of nicotine receptors compared to male nonsmokers. But surprisingly, women smokers had about the same number of nicotine receptors as nonsmokers. "When you look at it by gender, you see this big difference," said study researcher Kelly Cosgrove, an assistant professor of psychiatry at Yale University School of Medicine. The findings are important because the main treatments for people who want to quit smoking are nicotine-replacement therapies, such as nicotine patches and gums. The study suggests women smokers may benefit more from other types of treatment that don't involve nicotine, including behavioral therapies, such as exercise or relaxation techniques, and non-nicotine containing medications, Cosgrove said. Elements of smoking not related to nicotine, such as the smell and act of holding a cigarette, may play a greater role in fueling the habit of women smokers, compared with men, Cosgrove said. Locating nicotine receptors Cosgrove and colleagues scanned the brains of 52 men and 58 women, about half of whom were smokers. The researchers examined nicotine receptors in the brain by using a radioactive marker that binds specifically to an important group of receptors that are primarily responsible for the body's physical dependence on nicotine, Cosgrove said. Smokers in the study had abstained from smoking for a week so that their nicotine receptors would be free to bind to the marker used for imaging. The researchers found that male smokers had about 16 percent more nicotine receptors in an area of their brain known as the striatum, 17 percent more in the cerebellum, and 13 to 17 percent more in the cortical region, or outside layer, of the brain compared with male nonsmokers. Female smokers, on the other hand, had similar numbers of nicotine receptors in these brain regions. Why are female brains different? Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in N.Y., agreed more attention should be paid to non-nicotine related smoking therapies. "You can replace all the nicotine you want, and people might still want to smoke," Horovitz said. For instance, smoking is a big stress reliever for some people. Even the act of deep breathing is a part of the habit, and breathing exercises may help smokers because they mimic puffing a cigarette, Horovitz said. The reason for the sex difference seen in the study is not known, but it may have something to do with levels of the hormone progesterone. Levels of this hormone fluctuate in females depending on the stage of the menstrual cycle, and are much higher after ovulation. The study found higher levels of progesterone were associated with a lower number of available nicotine receptors, the researchers said, suggesting progesterone may indirectly block these receptors. The study is published in the April issue of Archives of General Psychiatry. Pass it on: Women smokers may not respond as well nicotine-replacement therapies as men. This story was provided by MyHealthNewsDaily, a sister site to LiveScience. Follow MyHealthNewsDaily staff writer Rachael Rettner on Twitter @RachaelRettner. Find us on Facebook.
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Otkriveno zašto se žene teško ostavljaju cigareta Za razliku od muškaraca, nikotinski nadomjesci, flasteri i žvake, ne djeluju na žene zbog specifične građe moždanih receptora Većina ljudi proklinje onaj dan kada su počeli sa jednom od najodvratnijih navika - pušenjem i iz petnih žila, s vremena na vrijeme, pokušavaju iz svog života izbaciti cigarete, no vrlo često taj trud neslavno završi, pogotovo ako ste žena. Naime, znanstvenici sa Sveučilišta Yale tvrde da je ženama teže nego muškarcima prestati pušiti jer njihov mozak drugačije reagira na nikotin. Kada netko puši broj nikotinskih receptora u mozgu, glavni krivaci za nastajanje ovisnosti o cigaretama, raste. Iako ta tvrdnja vrijedi za muškarce, na opće iznenađenje istraživača, ona je apsolutno neistinita za žene jer je otkriveno da one imaju sličan broj živčanih nastavaka kao i nepušači. Ova spoznaja je važna jer pokazuje da glavno oruđe za borbu protiv pušenja - nikotinski supstituti, poput žvakaćih guma i flastera - ne djeluju na žene. Znanstvenici smatraju da bi pripadnicama ljepšeg spola u odvikavanju više pomogle alternativne metode poput bihevioralnih terapija, tjelovježbi ili tehnike opuštanja. Znanstvenici su također zamijetili da pasivno pušenje i samo držanje nezapaljene cigarete između prstiju može pojačati ženama želju za nikotinom. Iako stručnjaci sa Yalea ne znaju objasniti otkrivene razlike između spolova, pretpostavljaju da ženski spolni hormon progesteron utječe na broj receptora za nikotin, odnosno što je više progesterona u tijelu to je manje receptora u mozgu. U studiji je sudjelovalo 52 muškarca i 58 žena, a oko polovice volontera bili su nepušači. Rezultati su objavljeni u stručnom časopisu Archives of General Psychiatry.