Effect of combinations of sodium salicylate and noise on the auditory thresholds of the chinchilla

Abstract

Thirty-nine monaural chinchillas were used to study the interaction between sodium salicylate and various TTS-producing noise paradigms. Five animals were included in each of the following three groups: (a) sodium salicylate (400 mg/kg) plus 2–4 kHz, 95-dB noise band for 1 hour; (b) sodium salicylate (400 mg/kg) plus 4-kHz CF noise band at 80 dB for 96 hours; and (c) sodium salicylate (400 mg/kg) plus 50 noise impulses having 50-μsec duration on 153-dB peak SPL, presented 1/min. The remaining 24 animals served as various controls in groups exposed to sodium salicylate or the noise paradigm alone. Thresholds were measured before, during, and after exposure using the AER technique. When sodium salicylate was combined with the various noise conditions, the maximum TTS values obtained from the combination studies were comparable to those obtained from the single agent producing the greatest TTS at a particular frequency. No consistent alteration in either magnitude or time course of post-treatment threshold shift was found following the combination treatments as compared to the individual agents alone. Hazard to the auditory system resulting from a combination of sodium salicylate and noise was concluded to be no greater than the hazard presented by either agent alone.