Effects of intravenous glycerol injection on inner ear fluid electrolytes

Under sodium pentrobarbital anesthesia (20-30 mg/kg, i.p.), normal guinea pigs received an intravenous injection of glycerol (1.0 ml/kg). Serum, cerebrospinal fluids (CSF) and inner ear fluids were collected from the scala tympani perilymph, scala vestibuli perilymph and the scala media endolymph. The sodium and potassium concentrations were assessed using microflame photometry. Increases in sodium concentration were found in the CSF and the scala tympani perilymph; no significant changes were observed in the serum, scala vestibuli perilymph or the scala media endolymph. These sodium increases were considered to be a result of the dehydration process caused by the osmotic agent glycerol. Increases in potassium concentration were found only in the scala vestibuli perilymph.