Scientists study nicotine's powerful hold on the brain

By SUSAN KREIMER
KNIGHT.RIDDER NEWSPAPERS

Debra Smith is craving to break her bondage to cigarettes.

In the morning, after parking her car in front of her workplace, she
lights up while listening to spiritual tapes on which ministers preach
about breaking any bad habit.

"It's something you don't want," the 36yearold bookkeeper said of her
smoking addiction. "You want to get rid of it. It's not good for you."

In her 21 years of puffing, Smith, of Cedar Lake, md., has tried to quit
seven or eight times. Her most successful attempt lasted three months.

As scientists discover more about nicotine's powerful hook on the brain,
they are better able to explain why the will to quit may not be enough to
keep Smith and other smokers away from cigarettes.

The research into nicotine addiction continues at a time when 29 states
have multibilliondollar health claims pending against the tobacco
industry. Former smokers and their families have also sued tobacco
giants, charging that cigarettes caused them to become ill. And while
one family last year won a $750,000 judgment against a cigarette
company, in May, a jury in Jacksonville, Fla., found R.J. Reynolds
Tobacco Co. not ]iab]e for the death of a 49yearold woman who died in
1995 after a lifetime of smoking.

Meanwhile, researchers studying the effects of nicotine on health have
found that it indeed alters brain chemistry And that may explain why
withdrawal symptoms like headaches, nervousness and irritability make
smoking a difficult habit to kick.

"Nicotine is taken up very rapidly in the brain," said Dr. Edythe
London, head of the brainimaging center at the National Institute on
Drug Abuse in Bethesda, Md.

Traveling twice as quickly through the bloodstream as mainlined heroin,
nicotine reaches the brain "within seven seconds of a drag," said Susan
Adrians, a chemical dependency therapist in the department of behavioral
medicine at St. Margaret Mercy Healthcare Centers South Campus in Dyer,
md.

Within a halfhour of smoking a cigarette, Adrians said, the nicotine
level "drops off slightly and the cravings set in."

After a person begins smoking, nicotine hinds to specific receptors in
the brain, changing its chemistry, experts say.

"A receptor is the equivalent of a biological keyhole (with nicotine
being the key)," said Dr. Jack Henningfield, associate professor at
Johns Hopkins Medical School in Baltimore.

"Nicotine exposure causes the body to end up with an increased number of
nicotine receptors," Henningfield said.

The brain then becomes accustomed to a continual level of nicotine, and
its pleasureinducing effects contribute to dependence, brain researcher
London said.

"Without the nicotine, there's an imbalance. So there are some
behavioral effects," she said.