内耳液電解質濃度に関する研究

浸透圧利尿剤について

抄録

Glycerol, an osmotic agent, was administered intravenously and orally to guinea pigs, and samples of serum, CSF, scala tympani perilymph, scala vestibuli perilymph and cochlear endolymph were collected. The concentrations of Na and K in these fluids were then assessed using microflame photometry (I. L. 443 Instrumentation Lab.).
1. Both Na and K concentrations in the CSF, scala tympani perilymph and scala vestibuli perilymph showed characteristic and individual distribution.
2. In order to clarify when the characteristic distribution establish we collected from fetuses and neonates. By the 49th day of gestation Na and K levels in the cochlear endolymph were already established. The K level in the scala tympani perilymph in the fetus was high and almost the same as that in the scala vestibuli perilymph.
3. When Reserpine was administered, the Na concentration in CSF, both perilymphs was markedly depressed and then observed almost the same level. This is thought to be attributable to the indirect blockage of energy producing systems in membrane transport of inner ear by the reserpine-induced depletion of catecholamines.
4. Glycerol (I. V.) increased the Na level in the CSF and scala tympani perilymph. K level was increased only in the scala vestibuli perilymph.
5. Glycerol (P. O.) increased the Na level in the CSF, scala tympani perilymph, scala vestibuli perilymph and scala media endolymph. K level was increased only in the scala tympani perilymph.
The increase of Na was considered to be the result of dehydration caused by the osmotic effect of glycerol. This action is slower and stronger after oral administration than after intravenous injection.
The present study suggests that the inner ear fluids in endolymphatic hydrops might be concentrated by the administration of diuretics, and that in the treatment of Meniere's disease, oral administration is more effective than intravenous injection.