Researchers have discovered that blocking the Sigma-1 receptor, a cellular protein, reduced binge eating and caused binge eaters to eat more slowly.

Binge eating disorder affects 15 million Americans and is believed to be the eating disorder that most closely resembles substance abuse and dependency.

Binge eaters typically gorge on junk foods excessively and compulsively despite knowing the adverse consequences, which are physical, emotional and social in nature.

Researchers understand that among bingers, normal regulatory mechanisms that control hunger do not function properly. Furthermore, binge eaters often experience withdrawal pains and other symptoms when they reduce their intake of junk food.

In the study, published online in the journal Neuropsychopharmacology, researchers showed that blocking the Sigma-1 receptor, a cellular protein, reduced binge eating and caused binge eaters to eat more slowly.

Researchers Pietro Cottone, Ph.D., and Valentina Sabino, Ph.D., both assistant professors at Boston University, developed an experimental model of compulsive binge eating by providing a sugary, chocolate diet only for one hour a day while the control group was given a standard laboratory diet.

Within two weeks, the group exposed to the sugary diet exhibited binge eating behavior and ate four times as much as the controls. In addition, the experimental binge eaters exhibited compulsive behavior by putting themselves in a potentially risky situation in order to get to the sugary food while the control group avoided the risk.

The researchers then tested whether a drug that blocks the Sigma-1 receptor could reduce binge eating of the sugary diet. Results showed that the drug successfully reduced binge eating by 40 percent, caused the binge eaters to eat more slowly and blocked the risky behavior.

The finding that binge behavior persists even in risky situations led the researchers to believe that there could be something wrong with how decisions were made.

Because evaluation of risks and decision making are functions executed in the prefronto-cortical regions of the brain, investigators then tested whether the abundance of Sigma-1 receptors in those regions was abnormal in the binge eaters.

Researchers discovered Sigma-1 receptor expression was unusually high in those areas, which could explain why blocking its function could decrease both compulsive binge eating and risky behavior.

If the Sigma-1 receptor does influence neurobiological alterations that lead to compulsive-like eating, researchers believe this could lead to development of new therapeutic treatments.

Source: Boston University

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