Effects of furosemide on the hearing loss induced by impulse noise

Shortly after furosemide injection, mice were exposed to simulated M16 rifle impulse noise produced by different loudspeakers and amplifiers in different exposure settings and, in other experiments, also to actual M16 rifle shots.Depending on the paradigm, the simulated noises either did not produce a TS, or the TS was reduced by furosemide. The drug was not effective in reducing TS resulting from actual impulse noise.Simulated M16 rifle impulse noise may not truly replicate the rapid rise time and very high intensity of actual rifle shots so that the TS following exposure to such noise can be reduced by these drugs. On the other hand, actual M16 impulse noise probably causes direct (frank) mechanical damage, which is not reduced by these drugs.Noise induced hearing loss (NIHL) affects many people in the world. The source of the noise can be industrial, recreational or military [1]. Therefore attempts have been made to prevent and alleviate the resulting impairment. These attempts include educational efforts [2], use of mechanical ear protecting devices [3] and pharmaceutical agents [4,5]. The types of noise can be broadly divided into two categories: continuous noise such as from personal music players, and impulse noise, for example that resulting from firearms. Much research has focused on the possible administration of drugs which could prevent the damage resulting from the exposure to continuous noise. Such research, besides suggesting drugs which could alleviate the NIHL, also provides insight into the possible mechanism of the NIHL caused by exposure to continuous noise. For example, it has been shown that if one administers, just before (but not after) a continuous noise exposure, drugs which reversibly reduce the magnitude of the active mechanical displacements produced in the cochlea in response to sound (temporarily depressing the cochlear amplifier, with reduced outer hair cell motility and decreased active basilar membrane displacement), the resulting p