The effects of acoustic stimulation on glucose utilization in the inner ear

Abstract

Glucose uptake into tissue can be mapped by the incorporation of 14C‐2‐deoxyglucose (2‐DG). However, this technique as employed in previous investigations does not lend itself to use in the cochlea. We have developed an alternative technique which permits the visualization of 2‐DG uptake in the tissues of the inner ear. 2‐DG (16 μCi/100 g in 0.1 ml) was injected intracardially into gerbils. Animals were exposed to wide band noise at intensities of 25, 45, 65, 85. or 105 dB SPL for one hour in a double‐walled sound attenuated chamber. Control subjects received no exposure. Gerbils were then sacrificed by decapitation, and the cochleas dissected whole and frozen in Freon 12 cooled to −160°C. Inner ears were then freeze‐dried. embedded in Epon or Spurr resin utilizing only organic solvents. and cut in mid‐modiolar section. Half cochleas were exposed on LKB Ultrofilm for 10 days. Control inner ears showed maximal uptake of 2‐DG in stria vascularis. Our initial data indicate that incorporation of 2‐DG increased in the spiral ganglion and VIIIth nerve during exposure to noise, especially at 85 and 105 dB SPL. [Work supported by NIH/NINCDS grants NS00176 and NS14945.]