A correlation of the effects of normoxia, hyperoxia and anoxia on PO2 of endolymph and cochlear potentials.
Change in PO2 in endolymph, endocochlear potentials and cochlear microphonics have been tested in normoxia, hyperoxia and anoxia on 24 guinea pigs. The polarographic method and construction of oxygen-sensitive microelectrodes is described in detail. The normal level of PO2 in endolymph vaires between 20 and 30 mm Hg. One-minute anoxia induced by breathing 100% N2 caused a decline in PO2, EP and CM, but during recovery only PO2 returned with over-correction to the preexposure level. Hyperoxia evoked by breathing 100% oxygen failed to increase the cochlear potentials and the PO2 in the endolymph. This suggests that vasoconstriction most likely occurs proximal to the capillaries bed of the stria vascularis.
D000818:Animals; D003051:Cochlea / Q000502:physiology*; D003055:Cochlear Microphonic Potentials; D004710:Endolymph / Q000378:metabolism*; D005072:Evoked Potentials, Auditory; D006168:Guinea Pigs; D007761:Labyrinthine Fluids / Q000378:metabolism*; D010101:Oxygen Consumption; D012119:Respiration