EFFECT OF STRESS ON COCHLEAR GLUCOCORTICOID PROTEIN .2. RESTRAINT

The effect of restraint stress via immobilization on rat cochlear gluc ocorticoid receptor (GR) levels was determined using an enzyme-linked immunosorbent assay (ELISA). Results demonstrated that GR levels in co chlear tissues exhibited tissue-specific and time-dependent responses to immobilization (6 hours daily). Similar responses of the GR were ob served in rats restrained during two different times of the day. A sig nificant quadratic trend (P = 0.019, R(2) = 0.58) was observed in leve ls of GR in spiral ligament tissues of rats restrained from 10:00 to 1 6:00 h; levels of GR were elevated by day 2, and by day 21 GR levels h ad returned to near normal levels. GR levels in the spiral ligament ti ssues also were found to increase significantly after 2 days in respon se to repeated restraint stress administered from 06:00 to 12:00 h (P = 0.017, R(2) = 0.34). Interestingly, a subtle, but statistically sign ificant, decreasing trend in the organ of Cord's GR levels was detecte d when the daily restraint stress was applied from 06:00 to 12:00 h fo r up to 7 days. No significant trends (P > 0.05) were observed in GR l evels of stria vascularis tissues regardless of the time of day of the restraint protocol. Stress has been implicated as an etiological fact or in Meniere's disease and other ear pathologies. The data presented here indicate that the effect of stress is specific to tissue region a nd that, as in tissues of other systems, the GR of cochlear tissues ar e responsive to stress.