The effect of glycerol on cochlear function and ionic concentration.

The use of glycerol continues to be a popular clinical test for diagnosing reversible hearing loss in patients with Meniere's disease, although its mechanism of action remains obscure. The purpose of this investigation was to study experimentally the alterations in the ionic composition and function of the cochlea which occur following glycerol administration. Immediate decreases in inner ear pressure and increases in AP threshold were seen. Delayed decreases in the endocochlear potential with increases in inner ear electrolytes occurred. However, we were unable to find any substantial changes in inner ear oxygen concentrations. Our findings support the concept that the principal action of glycerol is in osmotic reduction of inner ear pressure.