Behaviour of Cytochrome Oxidase Activity in the Cochlea of the Guinea-Pig Following Acoustic Stimulation

After having schematically drawn attention to the distribution of cyto-chrome oxidase in the cochlea of the normal guinea-pig (described in a former work) and the principal data of the literature relating to the histoche-mical and biochemical variations shown in the inner ear subsequent to sound stimulation, the authors describe the method of the investigation and its results. Intense sound stimulation (100 decibels) with pure tones of diverse frequencies (250, 2000, 4000, 8000 Hz), for a period of 3 hours, brings about a histochemically demonstrable reduction of enzymatic activity; this reduction is diffuse, does not depend on the frequency used, and is apparent not only at the level of the organ of Corti but also, more especially, at the site of the stria vascularis and the external spiral sulcus. These results are then briefly commented upon.