The Hearing Journal: Noise-Induced Tinnitus Linked to Lower Potassium Channel Activity
New research has identified a particular cellular mechanism associated with the induction of tinnitus in an animal model, representing an important step forward in the effort to better understand and treat this common auditory disorder.
“What had been known from others and our work is that once mice are exposed to loud sounds, some of them develop tinnitus, and the ones that develop tinnitus have hyperactive auditory systems,” said Thanos Tzounopoulos, PhD, senior author of the study, which was published in Proceedings of the National Academy of Sciences.“We wanted to figure out the cellular mechanism that leads to this hyperactivity,” said Dr. Tzounopoulos, who is associate professor of otolaryngology and neurobiology at the University of Pittsburgh.
In the study, 51.4 percent of 35 mice exposed to noise showed behavioral evidence of tinnitus. Using brain slices that contained the dorsal cochlear nucleus—an auditory brainstem nucleus previously implicated in tinnitus induction—Dr. Tzounopoulos and colleagues showed a reduction in KCNQ potassium channel activity in mice with tinnitus compared with control mice and mice who did not develop tinnitus after noise exposure. This decreased activity was restricted to the same regions that showed tinnitus-specific hyperactivity—those sensitive to high-frequency sounds.