Washington, Oct 24 ANI: A new study has revealed that roundworms' sense of smell plays a crucial role in controlling their metabolism and life span. The study suggests that roundworms deprived of the sense of smell are likely to have longer lifespan. Conducted by researchers from Washington University School of Medicine in St. Louis, it has shown that roundworms' life spans can be extended even when they are well fed - with just a chemical those blocks their sense of smell. In a 2005 study led by Dr Kerry Kornfeld, researchers had discovered class of anticonvulsant medications made the roundworm Caenorhabditis elegans live longer. However, the mechanism behind it was unknown. "We've learned that the drugs inhibit neurons in the worm's head that sense chemicals in their surroundings - the neurons are like the worm's nose," said Kornfeld, professor of developmental biology. "Like roundworms that are grown in a food-scarce environment, the worms exposed to the anticonvulsant ethosuximide lived longer. "But these worms ate plenty of food. That suggests that the worms' sensation of food is critical to controlling their metabolism and life span," Kornfeld added. If roundworms sense that food is abundant, their metabolism adjusts accordingly. Their bodies respond to promote rapid ingestion, rapid growth and rapid aging, said Kornfeld. In contrast, when the worms sense a shortage of food, they make "metabolic decisions" to delay growth, delay energy use and extend lifespan. Previous studies had shown that some human anticonvulsants slow aging in C. elegans. Now, further investigating the effect of one of those compounds, ethosuximide, the researchers found that it had the same life-extending effect as some well-studied genetic mutations in C. elegans. These mutations inhibit the activity of some sensory neurons in the worm, and that helped the researchers conclude that ethosuximide also directly affected these neurons. Roundworms treated with ethosuximide lived up to 29 percent longer than normal. The findings appear in the issue of Public Library of Science Genetics. ANI