Yl. Ma et al., COMBINED EFFECTS OF ADRENALECTOMY AND NOISE EXPOSURE ON COMPOUND ACTION-POTENTIALS, ENDOCOCHLEAR POTENTIALS AND ENDOLYMPHATIC POTASSIUM CONCENTRATIONS, Hearing research, 91(1-2), 1995, pp. 79-86
The effects of removal of endogenous corticosteroids via bilateral adr
enalectomy in combination with noise exposure (30 min at 100 dB) were
determined by recording compound action potentials (CAP) and endocochl
ear potentials (EP), and by measuring potassium concentrations (K-e(+)
) within the endolymph. Thirty-eight Long-Evans rats were divided into
groups according to experimental treatments: adrenalectomy (ADX) or n
on-ADX and noise exposure or non-noise exposure. CAP thresholds, EP an
d K-e(+) values were subjected to repeated-measures analysis of varian
ce with group and time as factors classifying the measurements. Noise
exposure resulted in significant elevations of CAP thresholds in both
the ADX and non-ADX animals, but had no effect on either EP or endolym
phatic K-e(+) Recovery was noted during all post-exposure measurement
periods and was significantly faster for ADX animals. EP and K-e(+) di
d not change during or after noise exposure. ADX animals showed a non-
significant reduction of EP and a statistically significant increase o
f K-e(+) during all measurement periods as compared to non-ADX animals
.