Alterations in Oxygenation of Cochlear Endolymph During Loud Sound Exposure

Abstract

The oxygen tension (pO₂) of endolymph of the guinea pig cochlea was measured during exposure to loud sound (12 kHz or high-pass noise; 110 dB SPL up to 1h duration). A small, but significant, steady decline in mean pO₂ was observed after both pure tone and high-pass noise exposure. The extent of the change in pO₂ varied from 0–50% in individual animals. compared with unexposed control animals. All exposed animals had an extensive loss of compound action potential (CAP) thresholds at frequencies of 8–30 kHz. However, there was no relationship between the extent of the change in pO₂ of endolymph and CAP threshold loss.

Key Words:

• oxygen microelectrode
• acoustic trauma
• endolymph