[Hair cell noise damage after improved hypoxia tolerance (author's transl)].

UNLABELLED: Guinea pigs were gradually adapted to a simulated altitude of 10,000 m. The round window microphone potential (RMP) frequency response was measured 24 hours after pure tone exposition (2.7 kHz, 130 dB, 1 hr). The electrophysiologically demonstrable sound induced damage of the organ of Corti of the adapted guinea pigs was significantly smaller than those of the nonadapted (normal) group. Altitude adapted animals: m = 18, Hb: 18.5 +/- 1.8 g%, Hc: 57.3 +/- 4.4+ RMP mean loss: 1.7 +/- 0.8 dB. CONTROLS: n = 18, Hb: 12.7 +/- 1.8 g%, Hc: 40.5 +/- 1.6%. RMP mean loss: 5.8 +/- 2.4 dB. All differences significant p less than 0.001. The evident possibility to reduce noise induced hair cell damage by means of previous adaptation to high altitude might be explained by the greater hypoxia tolerance and perhaps additional better oxygen supply to the receptor cells.