You are here:
TRIMETHYLTIN EFFECTS ON AUDITORY FUNCTION AND COCHLEAR MORPHOLOGY
Citation:
Crofton, K., K. Dean, M. Menache, AND R. Janssen. TRIMETHYLTIN EFFECTS ON AUDITORY FUNCTION AND COCHLEAR MORPHOLOGY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-90/236 (NTIS PB91117028), 1990.
Description:
TMT is neurotoxicant known to alter auditory function. he present study was designed to compare TNT-induced auditory dysfunction using behavioral, electrophysiological, and anatomical techniques. dult male long Evans hooded rats (n=9-l2/group) were acutely exposed to saline, 3, 5, or 7 mg/kg TNT. uditory thresholds were determined 11 weeks post-dosing for 5 and 40 kHz tones using reflex modification of the auditory startle response (ASR). rainstem auditory evoked response (BAER) thresholds were determined for 5, 40, and 80 kHz tonal stimuli 9 weeks post-dozing. ochlear histology was assessed at 13 weeks post-dosing. unctional endpoints demonstrated a high-frequency hearing loss. SR thresholds for 40 kHz tones were elevated 25-35 dB in all dosage groups. AER thresholds for 40 and 80 kHz tones were elevated 30-50 dB in the 5 and 7 mg/kg groups. rgan of Corti surface preparations revealed a pattern of damage suggesting classical ototoxicity. hat is, outer hair cells died preferentially in regions associated with high-frequency hearing, in a dosage-dependent manner from base to apex. hese data demonstrate the utility of the ASR and BAER in detecting functional alterations in audition and indicate that TNT-induced high-frequency hearing loss is associated with cochlear damage.