SMOKE & DOPE

What does smoking a cigarette have in common with snorting cocaine? Not a great deal, or so most people like to believe. In fact, for weeks Bob Dole has been playing into the conventional wisdom–and the hands of his supporters in the tobacco industry–by saying on campaign stops across the country that though nicotine may be habit forming, that doesn’t necessarily make it addictive. Scientists, however, say otherwise. And last week, in an article published by the journal Nature, a team of Italian researchers provided perhaps the most compelling reason yet to classify nicotine as an addictive drug.

The research was done on rats that had been injected intravenously with a small dose of nicotine, about as much as a smoker receives from a single drag on a cigarette. The team, led by Gaetano di Chiara, a neuroscientist at the University of Cagliari, then monitored the biochemical changes that occurred in the nucleus accumbens, an area of the brain that appears to control the process of addiction.

What the researchers found was striking. Levels of a powerful brain chemical called dopamine dramatically increased in the outermost shell of the nucleus accumbens, a region that is richly endowed with connections to one of the brain’s most important emotional centers, an ancient structure known as the amygdala.

Why is this important? A virtually identical pattern of biochemical activity, Di Chiara’s group had earlier established, accompanies injections of cocaine, amphetamines and morphine. The brain, in other words, appears to make no distinction between addictive drugs and what smokers prefer to think of as just a bad habit.

–By J. Madeleine Nash/Chicago