The effects of cetrimide and potassium bromate on the potassium ion concentration in the inner ear fluid of the guinea-pig

The mammalian inner ear is located deep within the temporal bone. The organ of Corti, the delicate sensory system for sound, is surrounded by two fluid systems; the potassium-rich endolymph and the sodium-rich perilymph. The pathogenesis of inner ear deafness is thought to be largely due to an imbalance of potassium and sodium ions in the inner ear fluids. Dynamic changes in K+ in the endolymph and perilymph were studied in the guinea-pig following cetrimide (cetrimonium bromide, a powerful cationic detergent which shows ototoxicity) applications on the round window membrane, intramuscular injection of potassium bromate (bread whitener, known to cause renal damage and permanent deafness in animals and man). Maximum fall in K+ concentration in the endolymoh (mM/min) and maximum K+ conductance (mM/min/mV) were 3.54 +/- 1.65 and 0.036 +/- 0.02 in cetrimide, and 1.85 +/- 0.35 and 0.021 +/- 0.009 in potassium bromate, respectively. In view of these findings, the influence of the active transport mechanism to K+ concentrations are discussed in comparison with dynamic changes in endolymph K+ induced by asphyxia and ethacrynic acid.