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Researchers in the University of Leicester's Department of CellPhysiology and Pharmacology have identified a cellular mechanismthat could underlie the development of tinnitus following exposure to loud noises. The discovery could lead tonovel tinnitus treatments, and investigations into potential drugsto prevent tinnitus are currently underway. Tinnitus is a sensation of phantom sounds, usually ringing orbuzzing, heard in the ears when no external noise is present. Itcommonly develops after exposure to loud noises (acousticover-exposure), and scientists have speculated that it results fromdamage to nerve cells connected to the ears. Although hearing loss and tinnitus affect around ten percent of thepopulation, there are currently no drugs available to treat orprevent tinnitus. University of Leicester researcher Dr Martine Hamann, who led thestudy published in the journal Hearing Research , said: "We need to know the implications of acoustic overexposure, not only in terms of hearing loss but also what'shappening in the brain and central nervous system. It's believedthat tinnitus results from changes in excitability in cells in thebrain - cells become more reactive, in this case more reactive toan unknown sound." Dr Hamann and her team, including PhD student Nadia Pilati, lookedat cells in an area of the brain called the dorsal cochlear nucleus- the relay carrying signals from nerve cells in the ear to theparts of the brain that decode and make sense of sounds. Followingexposure to loud noises, some of the nerve cells (neurons) in thedorsal cochlear nucleus start to fire erratically, and thisuncontrolled activity eventually leads to tinnitus. Dr Hamann said "We showed that exposure to loud sound triggershearing loss a few days after the exposure to the sound. It alsotriggers this uncontrolled activity in the neurons of the dorsalcochlear nucleus. This is all happening very quickly, in a matterof days" In a key breakthrough in collaboration with GSK who sponsored DrPilati's PhD, the team also discovered the specific cellularmechanism that leads to the neurons' over-activity. Malfunctions inspecific potassium channels that help regulate the nerve cell'selectrical activity mean the neurons cannot return to anequilibrium resting state. Ordinarily, these cells only fire regularly and therefore regularlyreturn to a rest state. However, if the potassium channels are notworking properly, the cells cannot return to a rest state andinstead fire continuously in random bursts, creating the sensationof constant noise when none exists. Dr Hamann explained: "In normal conditions the channel helps todrag down the cellular electrical activity to its resting state andthis allows the cell to function with a regular pattern. Afterexposure to loud sound, the channel is functioning less andtherefore the cell is constantly active, being unable to reach itsresting state and displaying those irregular bursts." Although many researchers have investigated the mechanismsunderlying tinnitus, this is the first time that cellular burstingactivity has been characterised and linked to specific potassiumchannels. Identifying the potassium channels involved in the earlystages of tinnitus opens up new possibilities for preventingtinnitus with early drug treatments. Dr Hamann's team is currently investigating potential drugs thatcould regulate the damaged cells, preventing their erratic firingand returning them to a resting state. If suitable drug compoundsare discovered, they could be given to patients who have beenexposed to loud noises to protect them against the onset oftinnitus. These investigations are still in the preliminary stages, and anydrug treatment would still be years away. Additional References Citations. We are high quality suppliers, our products such as China Belly Ring Jewelry , China Dermal Anchor Jewelry for oversee buyer. To know more, please visits Ear Flesh Tunnel.
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