For some, it’s love at first puff. For others, it’s just plain sickening. Why do smokers have such different reactions to their first cigarette—and why are some so much more tempted to try a second?
It’s all about the pleasure, the reward… and the neurotransmitter dopamine, according to researchers at the University of Western Ontario. The scientists have identified a specific pathway in the brains of rats that uses dopamine to relay signals associated with nicotine’s rewarding properties. The chemical pathway, called the “mesolimbic” dopamine system, is also involved with the addictive effects of alcohol and cocaine. The naturally occurring differences in dopamine receptors, says team leader Steven Laviolette, may explain why some people are more vulnerable to nicotine addiction.
But what if we were able to switch the message these receptors carried? Laviolette’s team found that by manipulating specific dopamine receptors, they were able to control whether rats found their exposure to nicotine enjoyable or repulsive. Rats that had had the equivalent of a “pack-a-day” addiction suddenly hated the chemical. Their withdrawal symptoms were eased as well.
We already understand how nicotine addiction works in dependent users, but Laviolette’s study is one of the first to explain why new smokers become hooked. Its findings could help the millions of people who start puffing cigarettes and then can’t seem to quit. If drugs could be developed to target specific nicotine receptors, smokers’ brains may stop perceiving the substance as a reward—and perhaps turn to something better—like chocolate—instead.
Image: Flickr/lanier67
