Volkow noted that prior studies had linked this form of the gene to obesity, and the new work "shows an association in the brain region that governs pleasure. The response is different with this polymorphism."
Studies of obese animals at Brookhaven National Laboratory have shown that dieting increases the D2 response to food, according to Peter Thanos, a neuroscientist at the lab. "If we could identify people who are more vulnerable, it would be fascinating to see what effect dieting has on their risk in terms of brain response," Thanos said. "No one has really done this in humans."
Diet pills aimed at the dopamine receptors won't work, Stice said. "These amphetamine-based diet pills are not the way to go," he said. Instead, Stice advocates early behavioral intervention that steers children away from fatty fast foods. "You want to change people's behaviors before they become entrenched," he said.
Exercise shouldn't be overlooked, Volkow added.
"Dieting is a complex process and people don't like it," she said. "Physical activity, which also activates the dopamine pathway, may be a mechanism for reducing the compulsive activity of overeating."
This work on obesity meshes nicely with drug-abuse studies, noted Volkow, who retains her laboratory position at Brookhaven. Both are instances of people engaging in compulsive behaviors, "even though they know it is very harmful," she said
There's more on dopamine at the University of Texas at Austin.
SOURCES: Eric Stice, Ph.D, scientist, Oregon Research Institute, Portland; Nora Volkow, M.D., director, National Institute on Drug Abuse, Bethesda, Md.; Peter Thanos, Ph.D, neuroscientist, Brookhaven national Laboratory, Brookhaven, N.Y.; Oct. 16, 2008, S
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