It's harder for individuals whose mothers smoked during pregnancy to quit the habit themselves, say researchers from Duke University Medical Center. Scientists have known for some time that prenatal exposure to nicotine is known to alter areas of the brain critical to learning, memory and reward. Now, researchers at the Duke Center for Nicotine and Smoking Cessation Research have discovered that these alterations may program the brain for relapse to nicotine addiction. Pregnant women who want to quit smoking should do so without the use of nicotine products such as patches or gums that also present a risk to the baby, the researchers said. "Smoking during pregnancy can harm the baby in ways that extend far beyond preterm delivery or low birth weight," said lead study investigator Edward Levin. "It causes changes in the brain development of the baby that can last a lifetime."
To arrive at their findings, appearing in the journal Pharmacology, Biochemistry and Behavior, the researchers exposed pregnant rats to nicotine. Once the offspring grew to adolescence, they were allowed to self administer nicotine as often as they wanted. To self administer the drug, the rats pressed a lever that caused a dose of nicotine to be delivered intravenously. Each push of the lever was roughly equivalent to a hit from a cigarette.
Duke researchers studied two groups of rats: those that had been exposed to nicotine prenatally and those that had not. Initially, both groups of rats consumed nicotine at the same rates -- about ten hits per session. After four weeks, the researchers forced the rats to go "cold turkey" for a week, during which they had no access to nicotine. Once the scientists restored access to nicotine again, they witnessed a dramatic difference in the rates at which the two groups resumed the habit. The rats that had been exposed prenatally took nearly double the nicotine hits compared with those that had not.
"It is easy to quit smoking - anyone can do it, for a brief time," Levin said. "But not taking it up again - that is the part that has proven so difficult for most people, especially those who have been exposed to nicotine before birth."
Source: Duke University Medical Center
