Biomaterial Database

Estimation of intracellular free magnesium using ion-selective microelectrodes: evidence for an Na/Mg exchange mechanism in skeletal muscle. 1991

L A Blatter

Department of Physiology, University of Maryland School of Medicine, Baltimore.

Mg-selective microelectrodes allow continuous direct recording of intracellular free magnesium concentration ([Mg]i). Mg-selective microelectrodes utilizing the neutral carrier ETH 1117 have been used to determine [Mg]i in a wide variety of tissues. However, this type of electrode suffers from considerable interference from other cations (primarily potassium and sodium when used for intracellular studies). The recently developed Mg sensor ETH 5214 reveals a much improved selectivity and sensitivity as compared to ETH 1117. For intracellular measurements of [Mg]i the interference from Na+, K+, Ca2+ and pH can be neglected. Measurements of resting [Mg]i in ferret ventricular muscle and frog skeletal muscle gave values of 0.85 and 0.93 mM, respectively. These values indicate that [Mg]i is not in a thermodynamic equilibrium and Mg2+ ions have to be extruded continuously from the cytoplasm against their electrochemical gradient. In skeletal muscle, measurements of [Mg]i and [Na]i under experimental conditions, which included changes of the membrane potential and the transmembrane gradients for Mg2+ and Na+, provided evidence that an Na/Mg exchange mechanism participates in maintaining [Mg]i at low cytoplasmic levels.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008839	Microelectrodes	Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)	Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D011896	Rana temporaria	A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.	European Common Frog,Frog, Common European,Common European Frog,Common Frog, European,European Frog, Common,Frog, European Common
D005289	Ferrets	Semidomesticated variety of European polecat much used for hunting RODENTS and/or RABBITS and as a laboratory animal. It is in the subfamily Mustelinae, family MUSTELIDAE.	Domestic Polecat,Domestic Polecats,European Polecat,European Polecats,Ferret,Mustela putorius,Mustela putorius furo,Polecat, Domestic,Polecat, European,Polecats, Domestic,Polecats, European
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
D017136	Ion Transport	The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.	Antiport,Ion Cotransport,Ion Exchange, Intracellular,Symport,Uniport,Active Ion Transport,Facilitated Ion Transport,Passive Ion Transport,Cotransport, Ion,Exchange, Intracellular Ion,Intracellular Ion Exchange,Ion Transport, Active,Ion Transport, Facilitated,Ion Transport, Passive,Transport, Active Ion,Transport, Ion