The receptor cells for acoustic stimuli are particularly vulnerable to reduced oxygen tension because of the limited characteristics of blood supply to the inner ear. Electrophysiological data have demonstrated that asphyxiation disrupts audition, but the consequences of mild, prolonged hypoxia upon the auditory system have not been investigated.
One aim of this investigation is to determine whether subchronic exposure to chemical asphyxiants at doses relevant to levels widely encountered in occupational and environmental settings produces ototoxicity. Chronic and impulse noise can induce auditory damage, but whether this occurs through mechanical trauma or by metabolic exhaustion is uncertain. Because there are data which show that noise reduces oxygen tension in the endolymph fluid of the scala media and produces vascular damage to the inner ear, it has been hypothesized that noise induced auditory loss may result from depressed oxygen availability. If noise does disrupt hearing by restricting oxygen to the Corti Organ or if it damages inner ear vascular structures it is logical to assume that noise would potentiate the ototoxic effects of chemical asphyxiant exposure.
The final aim of this proposal will be to specify the nature of the interaction between noise and chemical asphyxiant exposure. The methods to be used include measures of modulation of the acoustic startle reflex by low intensity test stimuli and subsequent histological examination of the inner ear.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Modified Research Career Development Award (K04)
Project #
5K04ES000125-04
Application #
3072671
Study Section
Toxicology Study Section (TOX)
Project Start
1983-09-01
Project End
1988-08-31
Budget Start
1986-09-01
Budget End
1987-08-31
Support Year
4
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Type
Schools of Public Health
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218