STANFORD, Calif. Scientists thought they had a good model to explain how the inner ear translates vibrations in the air into sounds heard by the brain. Now, based on new research from the Stanford University School of Medicine, it looks like parts of the model are wrong.
Anthony Ricci, PhD, associate professor of otolaryngology, and colleagues at the University of Wisconsin and the Pellegrin Hospital in France found that the ion channels responsible for hearing aren't located where scientists previously thought. The discovery turns old theories upside down, and it could have major implications for the prevention and treatment of hearing loss.
"I had thought that the channels were in a very different place," said Peter Gillespie, PhD, professor of otolaryngology at Oregon Health and Science University, who was not involved with the study. "This changes how we look at all sorts of previous data." The findings will appear in the May issue of Nature Neuroscience.
Ricci explained, "Location is important, because our entire theory of how sound activates these channels depends on it. Now we have to re-evaluate the model that we've been showing in textbooks for the last 30 years."
Deep inside the ear, specialized cells called "hair cells" sense vibrations in the air. The cells contain tiny clumps of hairlike projections, known as stereocilia, which are arranged in rows by height. Sound vibrations cause the stereocilia to bend slightly, and scientists think the movement opens small pores, called ion channels. As positively charged ions rush into the hair cell, mechanical vibrations are converted into an electrochemical signal that the brain interprets as sound.
But after years of searching, scientists still haven't identified the ion channels responsible for this process. To pinpoint the channels' location, Ricci and colleagues squirted rat stereocilia with a tiny water jet. As pressure from the water bent the stereoc
|Contact: Tracie White|
Stanford University Medical Center