Physiological dimensions of ototoxic responses in a model fish species

Pharmaceutical agents known to be toxic to the human auditory system also impair sensory hair cells of teleosts, and this supports the use of fish models for the screening of such compounds. However, previous investigations have focused almost exclusively on anatomical changes after drug administration without assessing macro-level physiological effects. Using the goldfish (Carassius auratus), we demonstrate that the acquisition of auditory evoked potentials offers a rapid and non-invasive means for tracking ototoxin-induced shifts in auditory thresholds. Gentamicin (100mg/mL) was the agent of choice as it is an extensively-studied human ototoxin. Significant shifts (p<0.05) in hearing sensitivity were observed between 300 Hz and 600 Hz and these shifts depended on acoustic pressure, but not particle motion. This differential elevation of auditory thresholds may be caused by impairment of specific populations of auditory sensory hair cells.