WASHINGTON - Turning all ear-related theories on their head, scientists have found that the ion channels responsible for hearing aren’t located where scientists reviously thought.
Researchers at the Stanford University School of Medicine have claimed that the age-old model to explain how the inner ear translates vibrations in the air into sounds heard by the brain is wrong.
The discovery by Anthony Ricci, PhD, associate professor of otolaryngology, and colleagues, could have major implications for the prevention and treatment of hearing loss.
“I had thought that the channels were in a very different place. This changes how we look at all sorts of previous data,” said Peter Gillespie, PhD, professor of otolaryngology at Oregon Health and Science University.
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, which slightly bend tiny clumps of hairlike projections, known as stereocilia, in the cells.
This movement, according to scientists, 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 research, scientists still haven’t identified the ion channels responsible for this process.
Thus, to pinpoint the channels’ location, researchers squirted rat stereocilia with a tiny water jet. As pressure from the water bent the stereocilia, calcium flooded into the hair cells.
The researchers used ultrafast, high-resolution imaging to record exactly where calcium first entered the cells. Each point of entry marked an ion channel.
To their surprise, the results showed that instead of being on the tallest rows of stereocilia, like scientists previously thought, the ion channels were located only on the middle and shortest rows.
Ion channels on hair cells not only convert mechanical vibrations into signals for the brain, but they also help protect the ear against sounds that are too loud.
Through a process called adaptation, the ear adjusts the sensitivity of its ion channels to match the noise level in the environment.
The findings will appear in the May issue of Nature Neuroscience. (ANI)
Related News
Space Shuttle Discovery returns to Earth after successful missionSeptember 12th, 2009 WASHINGTON - Space shuttle Discovery and its crew of seven astronauts has returned to Earth after a successful mission called STS-128, in which the team delivered two refrigerator-sized science racks to the International Space Station (ISS). One rack will be used to conduct experiments on materials such as metals, glasses and ceramics.
Space shuttle Discovery undocks from ISSSeptember 8th, 2009 WASHINGTON - The space shuttle Discovery undocked from the International Space Station (ISS) Tuesday after delivering supplies and equipment to boost the capacity of the orbiting laboratory. Pilot Kevin Ford backed Discovery away from the station at 1926 GMT for the trip back to Earth.
US shuttle Discovery arrives at space stationAugust 31st, 2009 WASHINGTON - US space shuttle Discovery arrived at the International Space Station (ISS) Sunday night after nearly two days of journey. Using space shuttle Discovery's reaction control system jets, Commander Rick Sturckow steered the shuttle to a soft docking with the ISS at 8.54 p.m.
Space shuttle Discovery set for Aug 25 launchAugust 19th, 2009 WASHINGTON - The space shuttle Discovery is scheduled to launch Aug 25 on a mission to deliver supplies and equipment to the International Space Station. A NASA review panel decided Wednesday that the shuttle is ready for the 1.36 a.m.
Traffic jams? MIT dons may have solutionJune 11th, 2009 WASHINGTON - Sick of spending countless hours in traffic jams? Frustrated with those jams which have no apparent cause -- no accident or stalled vehicles? A team of Massachusetts Institute of Technology (MIT) mathematicians may have the answer to your traffic woes. Phantom jams are those when there is no apparent reason -- when no lanes are closed for construction, there is no accident nor are there any stalled vehicles.
Smell of space is funny, say Discovery pilotsMarch 29th, 2009 WASHINGTON - The space shuttle Discovery and its crew of seven have safely returned to Earth. But the one thing pilots can't get out their noses is space's "weird" smell.
Biblical scholar to co-host Discovery channel series on Jesus ChristMarch 29th, 2009 WASHINGTON - A University of Illinois at Chicago biblical scholar will co-host "Who Was Jesus?," a new Discovery Channel documentary series that explores the life of Jesus and life in the first century. The documentary, co-hosted by University of Illinois at Chicago biblical scholar Rachel Havrelock, premieres on April 5, Palm Sunday.
Discovery astronauts finish third, final spacewalkMarch 24th, 2009 WASHINGTON - Two Discovery space shuttle astronauts completed maintenance work Monday on the International Space Station during the final spacewalk of the ongoing mission in orbit. During the six-and-a-half hour spacewalk, astronauts Joseph Acaba and Richard Arnold repositioned an equipment cart, deployed an external cargo mounting mechanism, lubricated the space station's robotic arm and reconfigured cables that power the station's gyroscopes.
Second maintenance operation begins on space stationMarch 22nd, 2009 WASHINGTON - Two astronauts from the Discovery space shuttle Saturday began a second spacewalk to perform maintenance work on the International Space Station, US space agency NASA reported. US astronauts Steve Swanson and Joseph Acaba will swap out batteries, fasten an antenna and install equipment for external storage, according to NASA.
Scientists come one step closer in detection of fundamental building block of natureMarch 21st, 2009 WASHINGTON - An international team of scientists has come a step closer to understanding the Universe with the discovery of a fundamental building block of nature. The recent discovery of a single top quark at the U.S.
Space shuttle Discovery docks with space stationMarch 18th, 2009 WASHINGTON - The space shuttle Discovery docked with the International Space Station (ISS) Tuesday for a construction mission that will allow the station to double its crew. The Discovery will deliver the fourth and final solar panel that will enable ISS to double the size of its crew to six astronauts.
Space shuttle Discovery lifts-off after delaysMarch 16th, 2009 WASHINGTON - Space shuttle Discovery blasted off for a construction mission to the International Space Station Sunday after weeks of delays. Discovery took off at 7.43 p.m.
Indian origin scientist plays key role in single top quark discoveryMarch 12th, 2009 WASHINGTON - A scientist of Indian origin has played a key role in discovering particle collisions that produce a single top quark, one of the fundamental constituents of matter. The scientist in question is Meenakshi Narain, professor of physics at Brown University, who has been involved with the CDF and DZero collaborations at the Department of Energy's Fermi National Accelerator Laboratory.
NASA postpones Discovery launchFebruary 22nd, 2009 WASHINGTON - NASA has for the fourth time delayed the launch of its space shuttle Discovery due to technical reasons, the US space agency has announced. After meeting all Friday at Kennedy Space Centre in Florida, shuttle managers decided against launching it in a week.
Launch of Discovery shuttle put off to Feb 27February 15th, 2009 WASHINGTON - NASA is eyeing Feb 27 as the earliest possible date for launch of the next shuttle mission Discovery, a postponement blamed on worries over the possibility that pieces of a faulty fuel valve could strike the shuttle on takeoff. In a statement over the weekend, NASA said it would give an update on plans next Friday.
Loading ...