title: Magnesium ion activity in the mammalian endolymph measured with ion-selective microelectrodes.
abstract: The free Mg++ concentration in endolymph was measured with Mg++-selective microelectrodes based on the neutral ligand ETH 1117. The property of Mg++ microelectrodes was obtained from calibration solutions, containing various Mg++ concentrations with the background electrolytes resembling endolymph. The range between 10 and 0.1 mM Mg++ concentrations changed the potentials of Mg++ microelectrodes by 14.4 +/- 3.0 mV. The endocochlear potential and the Mg++ concentration in the endolymph were 82.0 +/- 5.0 mV and 0.77 +/- 0.29 mM in the guinea pig, and 84.4 +/- 4.9 mV and 1.12 +/- 0.24 mM in the chinchilla, respectively. These results are discussed in the light of the dependence of Na+, K+-ATPase and its interaction with Ca++.
authors.affiliation: Department of Otolaryngology, University of Minnesota Medical School, Minneapolis 55414.
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Morizono
authors.forename: J
authors.initials: J
authors.lastname: Kusakari
authors.forename: T
authors.initials: T
authors.lastname: Takasaka
mesh_terms: D000818:Animals; D002682:Chinchilla; D003051:Cochlea / Q000502:physiology / Q000503:physiopathology; D004594:Electrophysiology; D004710:Endolymph / Q000032:analysis*; D006168:Guinea Pigs; D000860:Hypoxia / Q000378:metabolism / Q000503:physiopathology; D007761:Labyrinthine Fluids / Q000032:analysis*; D008274:Magnesium / Q000032:analysis*; D008839:Microelectrodes
chemical_list: D008274:Magnesium