Isoflurane blocks temporary tinnitus

Temporary tinnitus is a common consequence of noise exposure, and may share important mechanisms with chronic tinnitus. Noise-induced hearing loss is the most prevalent cause of chronic tinnitus. The reversibility of temporary tinnitus offers some practical experimental advantages. We therefore adapted a behavioral method based on gap detection to measure temporary tinnitus following brief acoustic trauma. Although anesthesia is often used during acoustic trauma exposure, many anesthetics can protect against noise-induced hearing loss. Whether anesthesia during acoustic trauma affects temporary tinnitus therefore remains an open question that directly affects experimental design in tinnitus studies. Here we tested whether anesthetizing rats with isoflurane during trauma had any effect on tinnitus. We found that gap-detection deficits, a behavioral measure of tinnitus, were 5 times stronger and lasted 10 times longer when isoflurane was not used. This suggests that isoflurane largely prevents temporary noise-induced tinnitus.