Abstract
Intracellular free Mg2+ concentrations ([Mg2+]i) in single rat brain neurons were measured with the Mg(2+)-sensitive fluorescent dye magfura-2. Addition of glutamate with glycine raised [Mg2+]i from 1 to more than 11 mM compared with the resting concentration of 0.5 mM, an effect mediated by N-methyl-D-aspartate receptors. Most of the increase in [Mg2+]i was independent of extracellular Mg2+, but was dependent on extracellular Ca2+. The second component of the increase induced by glutamate was independent of extracellular Ca2+, but required extracellular Mg2+ and was amplified by extracellular Na+ removal. These results indicate that regulation of [Mg2+]i by neurotransmitters such as glutamate may be important in controlling neuronal excitability.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Calcium / metabolism
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Cells, Cultured
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Cerebral Cortex / metabolism*
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Embryo, Mammalian
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Fluorescent Dyes
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Fura-2 / analogs & derivatives
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Glutamates / pharmacology*
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Glutamic Acid
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Glycine / pharmacology
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Kainic Acid / pharmacology
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Kinetics
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Magnesium / metabolism*
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N-Methylaspartate / pharmacology
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Neurons / drug effects
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Neurons / metabolism*
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Rats
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Receptors, N-Methyl-D-Aspartate / drug effects
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Receptors, N-Methyl-D-Aspartate / physiology*
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Veratridine / pharmacology
Substances
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Fluorescent Dyes
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Glutamates
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Receptors, N-Methyl-D-Aspartate
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2-(2-(5-carboxy)oxazole)-5-hydroxy-6-aminobenzofuran-N,N,O-triacetic acid
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Glutamic Acid
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N-Methylaspartate
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Veratridine
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Magnesium
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Kainic Acid
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Calcium
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Glycine
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Fura-2