In a discovery suggesting that odors may have a far more important role in life than previously believed, scientists have found that heart, blood, lung and other cells in the body have the same receptors for sensing odors that exist in the nose. It opens the door to questions about whether the heart, for instance, "smells" that fresh-brewed cup of coffee or cinnamon bun, according to the research leader, who spoke here today at the 245th National Meeting & Exposition of the American Chemical Society, the world's largest scientific society.
Peter Schieberle, Ph.D., an international authority on food chemistry and technology, explained that scientists thought that the nose had a monopoly on olfactory receptors. Located on special cells in the mucus-covered olfactory epithelium in the back of the nose, olfactory receptors are docking ports for the airborne chemical compounds responsible for the smell of food and other substances. Those molecules connect with the receptors, triggering a chain of biochemical events that register in the brain as specific odors. But discovery of olfactory receptors on other, non-olfactory cells came as a surprise.
"Our team recently discovered that blood cells - not only cells in the nose - have odorant receptors," said Schieberle. "In the nose, these so-called receptors sense substances called odorants and translate them into an aroma that we interpret as pleasing or not pleasing in the brain. But surprisingly, there is growing evidence that also the heart, the lungs and many other non-olfactory organs have these receptors. And once a food is eaten, its components move from the stomach into the bloodstream. But does this mean that, for instance, the heart 'smells' the steak you just ate? We don't know the answer to that question."
His team recently found that primary blood cells isolated from human blood samples are attracted to the odorant molecules responsible for producing a certain aroma. Schieberle described one experiment in which scientists put an attractant odorant compound on one side of a partitioned multi-well chamber, and blood cells on the other side. The blood cells moved toward the odor.
"Once odor components are inside the body, however, it is unclear whether they are functioning in the same way as they do in the nose," he stated. "But we would like to find out."
Schieberle's group and colleagues at the Technical University of Munich work in a field termed "sensomics," which focuses on understanding exactly how the mouth and the nose sense key aroma, taste and texture compounds in foods, especially comfort foods like chocolate and roasted coffee.