Age-related hearing changes and effects of exotoxin on inner ear function in aging rat. A frequency-specific auditory brainstem response study.
Frequency-specific auditory brainstem responses to tone bursts (2-31.5 kHz) and tuning curves were recorded in 8 male rats during their entire life. No significant threshold elevation occurred during the 1st year. Mean age at onset of hearing loss was 20 months, with individual variations ranging from 14 up to 23 months. In most animals, threshold elevations were limited to 20 and 31.5 kHz. At age of 18-23 months, 3 rats were treated with Pseudomonas aeruginosa exotoxin A. After instillation, threshold elevation occurred at all frequencies, followed by near-total recovery at low frequencies, but only partial reversibility at high frequencies. It is concluded that aging-related hearing changes in Sprague-Dawley albino rats start at different ages, particularly comprising high frequencies and encroaching on the middle and low areas with increasing age.
Stenqvist
M
M
Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital (Akademiska sjukhuset), Uppsala, Sweden. Monika.Stenqvist@ent.uas.se
D000375:Aging / Q000502:physiology*; D000818:Animals; D001309:Auditory Threshold; D007758:Ear, Inner / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem; D005098:Exotoxins / Q000494:pharmacology; D006309:Hearing / Q000187:drug effects / Q000502:physiology*; D008297:Male; D011550:Pseudomonas aeruginosa; D051381:Rats; D017207:Rats, Sprague-Dawley
D005098:Exotoxins