June 10, 2011

Brain Mechanism Explains Nicotine’s Appetite Suppressant

A team of scientists led by Yale School of Medicine has discovered a brain mechanism that explains how nicotine suppresses appetite "“ findings that could someday help develop medications to help people quit smoking without gaining weight. 

While previous research shows the average weight gain after quitting smoking is less than 10 pounds, fear of gaining weight can discourage some people from kicking the habit.

The current study revealed that a specific subclass of brain nicotinic receptor is involved in nicotine's ability to reduce food intake in rodents.   Specifically, the researchers found that a nicotine-like drug, cytisine, activated nicotinic receptors in the hypothalamus - a brain center that controls feeding.  This resulted in the activation of a circuit that reduced food intake and body fat in a mouse model.

The effect was very specific, since a drug that prevented cytisine from binding to its hypothalamic receptors blocked the reduction in food intake.

"These mouse models allow us to explore the mechanisms through which nicotine acts in the brain to reduce food intake," said the study's senior author Dr. Marina Picciotto of Yale University.

"We found that nicotine reduced eating and body fat through receptors implicated in nicotine aversion and withdrawal rather than reward and reinforcement.

Dr. Nora D. Volkow, director of the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health, which funded the research, said the research could help pave the way to new treatments to help people quit smoking without adding pounds.

"These results indicate that medications that specifically target this pathway could alleviate nicotine withdrawal as well as reduce the risk of overeating during smoking cessation," she said.

"Although more research is warranted, such a highly selective compound might be more effective than drugs that act on more than one type of nicotinic receptor."

The study is published June 10 in the journal Science. 


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