Intracellular Mg2+ diffusion within isolated rat skeletal muscle fibers
| Autor: | Claude Collet, Vincent Jacquemond, Jean Claude Bernengo |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Male
inorganic chemicals Molecular diffusion Magnesium pidolate Magnesium Diffusion Muscle Fibers Skeletal Organic Chemistry Biophysics Analytical chemistry chemistry.chemical_element In Vitro Techniques Biochemistry Silicone grease Rats Rats Sprague-Dawley chemistry.chemical_compound Silicone chemistry Animals Muscle Skeletal Microinjection Intracellular |
| Zdroj: | Biophysical Chemistry. 89:35-51 |
| ISSN: | 0301-4622 |
| Popis: | Intracellular free magnesium concentration ([Mg2+]i) was measured in enzymatically isolated rat skeletal muscle fibers using the fluorescent dye mag-indo-1. The change in [Mg2+]i produced by a local intracellular microinjection of magnesium pidolate (magnesium pyrrolidone carboxylate) was measured at a given distance from the injection site. In one series of experiments this protocol was tested on isolated fibers that were completely embedded into silicone grease: under these conditions, the injection produced an increase in [Mg2+]i that reached a steady level some time following the injection. The time-course of the [Mg2+]i change could be well accounted for by a model of longitudinal diffusion. The mean apparent Mg2+ diffusion coefficient (D(app)) was 188+/-9 microm2 s(-1) (n = 16), approximately four times lower than the value measured in vitro. This reduction likely results from the effects of cytoplasmic viscosity and of Mg2+ binding to low affinity static sites. Another series of measurements was performed on fibers that were either partially or completely free of silicone: under these conditions, the time course of the change in [Mg2+]i was in many cases more complex than predicted by simple diffusion. |
| Databáze: | OpenAIRE |
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