Professors William Bendena and Ian Chin-Sang joined hands to work with tiny, transparent worms that have similar neurotransmitters (chemicals that transmit nerve impulses) as humans. They found that when a specific nerve receptor is deleted, the worms lose interest in foraging for food, become slow-moving, and accumulate fat at a much higher rate than normal worms.
"Although there is a wealth of scientific data currently being collected regarding classic brain neurotransmitters, it's still uncertain how neuron connections may be either stimulatory or inhibitory in various organisms," says Dr. Bendena.
"Our breakthrough came when Dr. Chin-Sang localized the worm's receptor to one specific connecting nerve cell," the researcher adds.
Modified worms showed no difference in behaviour from their normal counterparts. However, upon being placed directly on food, they stopped their normal foraging behaviour, dramatically slowing their movements, and gained fat more quickly than normal worms.
When the researchers added extra copies of the receptor to the mutant worms, they became hyperactive and travelled large distances away from their food.
The researchers say that this type of receptor is an inhibitory switch within one connecting cell, and that worms defective in the receptor will gain fat.
"Such clearly affected behaviour and physiological changes have never been seen nor understood until this discovery," says Dr. Bendena.
"We hope that this will provide a basis for further research to unlock the mystery of the long-awaited nervous system connection to obesity," the researcher adds.
The study, partially funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), has been published on-line in the journal Proceedings of the National Academy of Sciences.