The effects of sodium salicylate on the cochlea of guinea pigs

A Characteristic of Aspirin-Induced Hearing Loss in Auditory Brainstem Response of Conscious Rats.

“…When sodium salicylate was administered subcutaneously to a guinea pig, electron microscopy revealed vacuolization of the endoplasmic reticulum in OHCs and chronic salicylate administration caused bending of the OHCs stereocilia [11]. Brownell and Winston [5] reported that the turgor of OHCs (in vitro) decreased in the presence of salicylate.…”

“…Most reports do agree that hearing loss and/or tinnitus are caused by these drugs. In almost all studies, the ototoxicity of aspirin and/or salicylate has been assessed in guinea pigs [8,11,27], monkeys [25,29] or cats [13,14,30], and little information is available on the effects of aspirin on the auditory function of rats. Recently it was indicated in rats that salicylate had a stronger effect on the otoacoustic emission distortion product for high and low frequencies with a clearly smaller effect for frequencies from the range of 6 to 8 kHz, and additionally, the loudness of salicylateinduced rat tinnitus was detected at moderate intensities corresponding to 62 dB SPL below 10 kHz by the behavioral response [18].…”

“…The extent of the hearing loss is also related to the plasma level of aspirin and the duration of the treatment [7,23]. However, the mechanism or site underlying aspirin and/or salicylate ototoxicity remains poorly understood.Generally, the mechanisms underlying the reversible hearing impairment produced by aspirin and salicylate may be considered to be as follows: in guinea pigs and/or rats, changes such as a decrease in prostaglandin (PG) synthesis by the lateral wall, a decrease in PG levels in perilymph [12] and a change in Ca 2+ movement in the cochlea related to the decreased PG levels [17] occurs and is followed by morphological changes in the outer hair cells (OHCs) in the cochlea [11]. There have been numerous investigations of the electrical activity in the cochlea or auditory nerve on a salicylate effect, e.g., cochlear microphonic (CM) [4,13,24,27,28,30], summating potential (SP) and endocochlear potential (EP) [27,30], compound action potential (CAP) of the auditory nerve [27,30,31] and suppression of active cochlear processes [21].…”

Frequency Selectivity on Aspirin-Induced Hearing Loss in Rats with Auditory Stimulus-Induced Conditioned Suppression.

“…From these previous investigations and our previous rat ABR study, it was suggested that aspirin action in rat might induce tinnitus without hearing loss which is most likely to be at the best frequency or centered at a small number of frequencies. It is reported in guinea pig that single dose of sodium salicylate results in vacuolization of the endoplasmic reticulum underlying the cell membrane in the outer hair cells (OHCs) [12]. In the same literature, inner hair cells (IHCs) showed minor but similar changes and chronic administration also caused bending of the OHCs stereocilia.…”

“…Most reports do agree that hearing loss and/or tinnitus are caused by aspirin; however, Boettcher and Salvi [2] reported that the results on the effects of aspirin on frequency selectivity are conflicting. To date, the ototoxicity of aspirin and/or salicylate has been assessed in guinea pigs [8,12,28], monkeys [27,30] or cats [14,15,31]. Rodents are preferable species, as the rat has an acoustic pathway similar to that of the cat and human [6,7,9], the experimental conditions for rodents are much more easily controlled and they are less expensive.…”