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Article: Effects of Intracellular and Extracellular Concentrations of Ca^sup 2+^, K+, and Cl- on the Na+-Dependent Mg^sup 2+^ Efflux in Rat Ventricular Myocytes
- Article from:
- Biophysical Journal
- Article date:
- July 1, 2006
- Author:
CopyrightCopyright Biophysical Society Jul 1, 2006. Provided by ProQuest LLC. (Hide copyright information)
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ABSTRACT
Intracellular Mg^sup 2+^ concentration ([Mg^sup 2+^]^sub i^) was measured in rat ventricular myocytes with the fluorescent indicator furaptra (25°C). After the myocytes were loaded with Mg^sup 2+^, the initial rate of decrease in [Mg^sup 2+^]^sub i^ (initial Δ[Mg^sup 2+^]^sub i^/Δt) was estimated upon introduction of extracellular Na^sup +^, as an index of the rate of Na^sup +^-dependent Mg^sup 2+^ efflux. The initial Δ[Mg^sup 2+^]^sub i^/Δt values with 140 mM [Na^sup +^]^sub o^ were essentially unchanged by the addition of extracellular Ca^sup 2+^ up to 1 mM (107.3 ± 8.7% of the control value measured at 0 mM [Ca^sup 2+^]^sub o^ in the presence of 0.1 mM ...