Smokers tend to be thinner than nonsmokers, and new research reveals the exact spot in the brain where nicotine's appetite-suppressing effects take hold. The findings could be harnessed and used as a weight-loss treatment, researchers say.
The researchers found a receptor on the surface of some brain cells that nicotine binds to, the study said. When they activated this receptor in mice, the mice ate less. The researchers hope the findings will carry over to humans.
A treatment based on these findings could allay smokers' common fear that quitting will bring weight gain, and could potentially augment the weight-loss efforts of non-smokers.
"What we've been able to find out is where in the brain [appetite suppression] happens, and find the receptors for nicotine in the brain that are responsible," said study author Marina Picciotto, a professor of psychiatry at Yale. "I'm hopeful that we'll be able to make medications based on these nicotine receptors that could be helpful in controlling appetite."
In the study, researchers manipulated genes for nicotine receptors in mouse brains. By altering the genes to turn off different receptors in different mice, they were able to pinpoint the group of nicotine receptors responsible for appetite suppression —a group known as [alpha]3[beta]4.
The researchers' mouse model drew praise for the precision it achieved.
"What I was most impressed at here is the exactness with which they were able to find the nicotine receptor subunits that mattered," said Elissa Chesler, a neurogeneticist at the Jackson Laboratory in Bar Harbor, Maine, who was not involved with the study. "If we can target that pathway...perhaps we can give people something that can control appetite that isn't associated with addiction to a harmful substance."
She said the results would likely carry over to people because in our cells, the processes at work are very similar to those in mice.
Picciotto said that future research in the area could help develop a better understanding of how the receptors work to harness appetite suppression.
As to the drug development possibilities, some potential treatments may already be around, Picciotto told MyHealthNewsDaily.
"It may be that things already being used for smoking cessation in humans could be repurposed," she said.
For example, she pointed to Tabex, a plant-based supplement used in Eastern Europe for smoking cessation, but is not available in the United States.
However, she noted human research on these receptors may prove tricky, as they are involved in the fight-or-flight response, and so activating them can raise heart rate and blood pressure.
"It may not be an easy receptor to target," she said.
Picciotto said she is optimistic that research in this area may ultimately help some people, but will not be a solution for all who seek a drug to help them lose weight. Smokers tend to gain an average of about five and a half pounds when they quit, she said, and the benefit from a drug would likely be in that range.
"It's not going to solve obesity by any means," she said.
"It could be helpful for people who are trying to quit smoking but are worried about weight gain but it may also help people who need another tool to try to help control appetite," Picciotto said.
The study was published today in the journal Science.