Changes in Cochlear Blood Flow during Acoustic Stimulation as Determined by ¹⁴C-iodoantipyrine Autoradiography

Abstract

Local blood flow was measured in the tissues of the cochlea using the [¹⁴C]iodoantipyrine autoradiographic technique. Flow observed without acoustic stimulation was compared with that seen during exposure to wide-band noise at 85 or 105 dB SPL. Compared with the un-exposed cochlea, substantial increases in blood flow were observed during exposure to 85 dB SPL noise in the spiral ganglion, VIII nerve and spiral lamina. Little or no change was noted in external wall structures. These results are consistent with changes in cochlear metabolism which have been reported previously using similar techniques, suggesting that increases in blood flow may be linked to increases in local metabolism. No changes in blood flow were measured during exposure to 105 dB SPL noise. This result is similar to those of other investigators using potentially damaging intensities of acoustic stimulation.

Key Words:

• circulation
• inner ear
• noise exposure