In 2003, Hatt and his colleagues showed that olfactory receptors in human sperm were functional and could be activated by an odor molecule, just like the receptors in the nose. Still, the findings were met with resistance from the field, Hatt says. “At the beginning it was really hard to convince my scientific colleagues that these olfactory receptors are not expressed exclusively in the nose.”

Over the next decade, Hatt’s team and others continued to identify olfactory receptors in a variety of human tissues, including the lungs, liver, skin, heart, and intestines. In fact, they are some of the most highly expressed genes in many tissues. “One can be sure that these receptors must have enormous importance for the cell,” Hatt says.

— Read more at What Sensory Receptors Do Outside of Sense Organs at The Scientist.