JUPITER, FL January 25, 2011 Embargoed by the journal Nature until January 30, 1 PM Eastern time Scientists from the Florida campus of The Scripps Research Institute have identified a pathway in the brain that regulates an individual's vulnerability to the addictive properties of nicotine. The findings suggest a new target for anti-smoking therapies.
The study appeared January 30, 2011, in an advance, online issue of the journal Nature.
In the study, the scientists examined the effects of a part of a receptor (a protein molecule to which specific signaling molecules attach) that responds to nicotine in the brain. The scientists found that animal models with a genetic mutation inhibiting this receptor subunit consumed far more nicotine than normal. This effect could be reversed by boosting the subunit's expression.
"We believe that these new data establish a new framework for understanding the motivational drives in nicotine consumption and also the brain pathways that regulate vulnerability to tobacco addiction," said Scripps Research Associate Professor Paul Kenny, who led the study. "These findings also point to a promising target for the development of potential anti-smoking therapies."
Specifically, the new study focused on the nicotinic receptor subunit α5, in a discrete pathway of the brain called the habenulo-interpeduncular tract. The new findings suggest that nicotine activates nicotinic receptors containing this subunit in the habenula, triggering a response that acts to dampen the urge to consume more of the drug.
"It was unexpected that the habenula, and brain structures into which it projects, play such a profound role in controlling the desire to consume nicotine," said Christie Fowler, the first author of the study and research associate in the Kenny laboratory. "The habenula appears to be activated by nicotine when consumption of the drug has reached an adverse level. But if the pathw
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Scripps Research Institute