A team of American and Italian neuroscientists has
identified a cellular change in the brain that accompanies obesity. The
findings could explain the body's tendency to maintain undesirable weight
levels, rather than an ideal weight, and identify possible targets for
pharmacological efforts to address obesity.
The findings, published in the Proceedings of the National
Academy of Sciences this week, identify a switch that occurs in neurons within
the hypothalamus. The switch involves receptors that trigger or inhibit the
release of the orexin A peptide, which stimulates the appetite, among other
behaviors. In normal-weight mice, activation of this receptor decreases orexin
A release. In obese mice, activation of this receptor stimulates orexin A
release.