Monday, August 10, 2009

Leptin influences our motivation to eat

As we all know from experience, people eat not only because they are hungry, but also because the food just simply tastes too good to pass up. Now, a new study in the August 6th Cell Metabolism, helps to explain how leptin, a hormone produced by fat tissue, influences that motivation to eat.

The researchers describe for the first time a new bunch of leptin-responsive (LepRb) neurons in the brain's lateral hypothalamic area (LHA). Those LHA neurons feed directly into the mesolimbic dopamine system seated in the ventral tegmental area (VTA) of the brain, which controls the rewarding properties we assign to things.

The study therefore adds to growing evidence that leptin doesn't turn the appetite on and off just by controlling satiety – for instance, whether we feel hungry or full.

"Some people may over-eat rewarding food because of a perceived 'reward deficit,'" researchers suggest. "When leptin is turned up, it might fix that deficit and make us feel better about a lot of things. In the future, it will be crucial to address the potential dysregulation of LHA neurons in states of obesity."

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