Just one cigarette leaves brain wanting more
NEW YORK (Reuters Health) - Puffing on a single cigarette can leave a lasting impression on the brain's pleasure center that primes it for nicotine addiction, new research shows. This glimpse at nicotine's early effects could lead to drug therapies to hel
In the brain, nicotine uses mechanisms similar to those involved in learning and memory to leave a nicotine "memory'' in the brain's "reward center,'' according to researchers at the University of Chicago, Illinois. The memory basically says: ''Nicotine is good.''
The investigators used brain tissue from rats to uncover the path nicotine takes to instill addiction. In doing so, they identified specific nicotine receptors that could be potential targets of drug therapy to quash addiction, Dr. Daniel S. McGehee told Reuters Health in an interview. The study findings are published in the August issue of the journal Neuron.
Scientists have known that nicotine triggers a release of the feel-good hormone dopamine. McGehee said this research shows that even small amounts of nicotine create a "long-term excitability'' in the connections between the brain cells that produce dopamine. The cells are then primed to react to the next nicotine exposure with a greater rush of dopamine.
According to McGehee, nicotine appears to attach to a specific receptor on dopamine-producing cells. Therefore, he said, a drug that blocks these receptors may help smokers kick the habit. While all addictive drugs affect dopamine levels, he noted, the process identified in this study seems to be unique to nicotine.
"It's a tragedy,'' McGehee said, "that cigarettes are such an easy delivery system to nicotine.''