The Effect of Furosemide on the Concentrations of Electrolytes in Inner Ear Fluids

Abstract

Serum, cerebrospinal fluid (CSF), scala vestibuli perilymph and scala tympani perilymph were collected from 286 normal anesthetized guinea pigs (sodium pentobarbital 20-30mg/kg I. P.) both before and after intravenous administration of furosemide (15mg/kg) and normal saline (1.5ml/kg). One hundred and twelve guinea pigs receiving normal saline were used as a control group. Then, the sodium and potassium concentrations were assessed using a microflame photometer (I. L. 443 Instrumentation Lab.).
Measurement was made of 104 normal guinea pigs to obtain the preinjection values as standards for the subsequent experiments.
Marked increase in the sodium concentration was observed both in the scala vestibule and tympani perilymphs, and slight increase was found in CSF, while there was no significant change in the serum.
The potassium concentration was increased in both scala vestibuli and tympani perilymphs, but there was no significant change in CSF or serum.
The results of the present study revealed that the increase in sodium concentration was a result of dehydration in the above-mentioned fluid spaces.
Changes in potassium concentration was found in both perilymphs, and this may not be attributable to such a simple process as dehydration. The elevation of these potassium concentrations will be understood when concomitant changes in the electrolytes in the endolymph are clarified, or considered the specific effects of Furosemide to these fluid spaces in the point of transport system of electrolytes.
For the elucidation of the effect of furosemide, the above findings of electrolyte concentrations should be further evaluated with respect to their possible significance.