Obesity may be wired in the brain, rat study suggests

Feb 05, 2008

A predisposition for obesity might be wired into the brain from the start, suggests a new study of rats in the February issue of Cell Metabolism.

Rats selectively bred to be prone to obesity show abnormalities in a part of the brain critical for appetite control, the researchers found. Specifically, the researchers show that the obese rats harbor defects in neurons of the arcuate nucleus (ARH) of the hypothalamus, which leaves their brains less responsive to the hunger-suppressing hormone leptin.

“The neurodevelopmental differences in these animals can be seen as early as the first week,” said Sebastien Bouret of the University of Southern California. “The results show that obesity can be wired into the brain from early life. The three-million-dollar question now is how to get around this problem.”

It is increasingly accepted that obesity results from a combination of genetic and environmental factors, the researchers said. Rodent models of obesity can provide valuable insights into the biological processes underlying the development of obesity in humans. The “diet-induced obese” (DIO) rats used in the current study are particularly suited to the task, according to Bouret, because their tendency to become overweight shares several features with human obesity, including the contribution of many genes.

Previous studies had suggested that the brains of DIO rats are insensitive to leptin, the researchers added. Circulating leptin, produced by fat tissue, acts as a signal to the brain about the body’s energy status. Leptin is also critical for the initial development of ARH neurons.

In the new study, the researchers examined the obesity-prone rats for signs of abnormal brain development. They found that the animals’ brains had fewer neural projections from the ARH, a deficiency that persisted into adulthood. Those projections are needed to relay the leptin signal received by the ARH to other parts of the hypothalamus, Bouret said.

The researchers found further evidence that those changes in brain wiring stem from a reduced responsiveness of the brain to leptin’s action during development.

“It seems [in the case of these rats] that appetite and obesity are built into the brain,” Bouret said. While their condition might be ameliorated by exercising and eating right, he added, the findings suggest that the propensity to gain weight can’t be reversed.

But there is hope yet. It’s possible that treatments delivered during a critical early period of development might be capable of rewiring the brain, Bouret said.

Source: Cell Press

Explore further: Revealing camouflaged bacteria

add to favorites email to friend print save as pdf

Related Stories

Antennae help flies 'cruise' in gusty winds

Apr 10, 2014

Due to its well-studied genome and small size, the humble fruit fly has been used as a model to study hundreds of human health issues ranging from Alzheimer's to obesity. However, Michael Dickinson, Esther ...

Scientist pushes boundaries of food sensory research

Mar 20, 2014

Anyone who has ever been lured by the call of a dozen fat- and sugar-laden donuts in the office break room while a healthy container of yogurt looks on helplessly can relate to Susan Duncan's research regarding ...

Bid to clean up the world

Sep 17, 2013

An international scientific initiative aimed at reducing the impact of human-made pollution on the health and wellbeing of the whole world was launched in Melbourne, Australia, today.

Recommended for you

Revealing camouflaged bacteria

41 minutes ago

A research team at the Biozentrum of the University of Basel has discovered an protein family that plays a central role in the fight against the bacterial pathogen Salmonella within the cells. The so cal ...

EU must take urgent action on invasive species

3 hours ago

The EU must take urgent action to halt the spread of invasive species that are threatening native plants and animals across Europe, according to a scientist from Queen's University Belfast.

User comments : 0

More news stories

Revealing camouflaged bacteria

A research team at the Biozentrum of the University of Basel has discovered an protein family that plays a central role in the fight against the bacterial pathogen Salmonella within the cells. The so cal ...

EU must take urgent action on invasive species

The EU must take urgent action to halt the spread of invasive species that are threatening native plants and animals across Europe, according to a scientist from Queen's University Belfast.

Progress in the fight against quantum dissipation

(Phys.org) —Scientists at Yale have confirmed a 50-year-old, previously untested theoretical prediction in physics and improved the energy storage time of a quantum switch by several orders of magnitude. ...