Science and Technology

Molecular mechanism of the fruit fly helps regulate appetite in humans

Scientists may reduce the propensity of obese individuals to eat too much when faced with food odors

Biologists at the University of California at San Diego, USA, have identified the molecular mechanisms triggered by hunger in fruit flies that improve the nervous system response to the smell, allowing these insects and to humans, hunters become more efficient when they are hunger.

Researchers hope the discovery could provide a potentially new way to regulate appetite in humans. Scientists may be able to reduce the propensity of obese individuals to overeat when faced with the smells of delicious foods.

The study

The research team, led by Jing Wang identified a neuropeptide and a receiving neuron that controls the fly's olfactory behavior that could be targeted by drugs to make changes in appetite, normally regulated by levels of insulin in the body.

"Our studies in Drosophila discuss an important issue - such as hunger modulates olfactory processing," noted Wang. "We were surprised to discover that the modulation of smell famine happens in the suburbs, because most of the literature on the regulation of feeding is about the function of the hypothalamus. There is evidence to suggest that this type of modulation in peripheral olfactory system is present in systems of vertebrates as well. "

While scientists had previously identified similar neuropeptides that control feeding behavior of vertebrates, was not known yet how these molecules control the smell or the behavior of an organism.

Wang and his team believed that by looking at the molecular mechanisms that allow the fruit flies to improve their search for food when insulin levels are low after a period of fasting, they would get a better understanding of this process.

They used a computerized system to monitor over time the position of flies well fed or hungry around a drop of apple cider vinegar, which served as a food source.

Results showed that during the observation period of 10 minutes, the flies went hungry most of the time walking around the food source, while flies fed roamed throughout the area with a preference for the perimeter.

The researchers found that surgical removal of the antennas used by flies to smell destroyed the propensity of the flies hungry from flying around the food source, as well as the genetic suppression of the production of neuropeptide F receptor, which scientists have discovered that increases in response to starvation or drop in insulin levels.

Using two-photon microscopy, the researchers found changes in specific neurons in the olfactory response dependent starvation.

"The notion that the modulation of peripheral olfactory system hunger is linked to insulin signaling has potential implications for therapeutic intervention in the epidemic of obesity in a large percentage of the population," said Wang.

The researchers identified the insulin receptor, PI3K, and short neuropeptide F receptor, which is also modulated by insulin levels, as potential molecular targets for the control of appetite in humans and other vertebrates.

However, the researchers said more research is needed to determine whether and to what extent insulin levels control the human olfactory sensitivity.