Development of Monovalent Ions in the Endolymph in Mouse Cochlea

• Published in: O.R.L. Journal for oto-rhino-laryngology and its related specialties Vol. 62; no. 5; pp. 241 - 246
• Main Authors: Yamasaki, Masayuki, Komune, Shizuo, Shimozono, Masami, Matsuda, Keiji, Haruta, Atsushi
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.09.2000; S. Karger AG
• Subjects: Animals; Animals, Newborn; Biological and medical sciences; Chlorides - metabolism; Cochlea; Electrodiagnosis. Electric activity recording; Electrophoresis, Agar Gel; Endolymph - metabolism; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Membrane Potentials; Mice; Mice, Inbred ICR; Nervous system; Original Paper; Potassium - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Sodium - metabolism; Sodium-Potassium-Exchanging ATPase - metabolism; Cochlea; Development; Ion; Endolymph; Endocochlear potential; Mouse; Monovalent cation; Rodentia; Reverse transcription; Exploration; Experimental study; Polymerase chain reaction; Electrodiagnosis; Vertebrata; Mammalia; Animal; Monovalent anion; Auditory evoked potential; Molecular biology
• ISSN: 0301-1569; 1423-0275
• DOI: 10.1159/000027753

The present study was designed to clarify the chronological developmental process of monovalent ions (Na + , K + , Cl – ) in the endolymph of the mouse in relation to the development of the endocochlear potential (EP). The EP and ionic concentrations were measured simultaneously with the ion-sensitive double-barreled microelectrodes from the scala media of the basal turn. The EP increased abruptly 7 days after birth (DAB) and reached approximately 80 mV 14 DAB. In the earliest postnatal days, the endolymphatic Na + concentration was significantly higher than that in adult mice, however, the K + and the Cl – concentrations were lower. The concentrations of all the monovalent ions in endolymph reached adult levels at 7 DAB when the EP was still under 20 mV. These data strongly suggest the presence of a different mechanism between the production of monovalent ions, especially of high K + in the endolymph and that of EP.