STUDIES ON ELECTROLYTES (SODIUM AND POTASSIUM) OF INNER EAR FLUID

A fine measurement of sodium and potassium of inner ear fluid was performed in large number of guinea pigs by means of flamephotometer, and the effect of acoustic stimulation and intravenous injection of 7% solution of sodium bicarbonate on sodium and potassium concentration was also inve-stigated.In normal guinea pigs, the concentration of sodium was higher in perilymph, than in endoly-mph while the relative concentration of potassium was reverse in perilymph and endolymph (endoly-mph: Na, 15.2±2.4meq/l. K, 131.5±2.8meq/l. peri-lymph in the Scala tymp.: Na, 149.5±5.5meq/l.K, 8.0±1.0meq/l. perilymph in the Scala vest.:Na, 148.5±2.7meq/l. K, 13.9±1.2meq/l).When the animal was exposed to an acoustic stimulus of white noise of 120phon for 8 hours, endolymph potassium decreased and perilymph sodium of scala tympani increased.Repetitive exposures to the same acoustic sti-mulation for a week further lowered the concent-ration of endoymph potassium accompaning with decrease of perilymph potassium.Pleyer's pinna reflex and histopathological fin-dings were also definintely altered by the repeated acoustic stimulation. After the rotatory stimulati-on, on the other hand, potassium concentration was elevated in both endolymph and perilymph with no essential change of sodium concentration.The change of concentration were all conside-red to be statistically significant.Contrary to the intravenous injection 5% solu-tion of sodium chloride, 7% solutiom of sodium bicarbonate did not significantly alter the sodium and potassium concentration during the observatory period of one to 24 hours after the injection.