Abstract
Recent studies have shown that glutamate excitotoxicity may be a component in the etiology of multiple sclerosis (MS). Glutamate transporters determine the levels of extracellular glutamate and are essential to prevent excitotoxicity. We have analyzed here the expression of the glutamate transporters EAAT1, EAAT2 and EAAT3 in control and in MS optic nerve samples. We observed an overall increase in the level of the glutamate transporters EAAT1 and EAAT2 mRNA and protein. In turn, functional assays showed that glutamate uptake was also increased in MS samples. Furthermore, glutamate transporter increases were mimicked in rat optic nerves treated with excitotoxic levels of glutamate. Together, these results indicate that enhanced expression of glutamate transporters in MS constitutes a regulatory response of glial cells to toxic levels of glutamate in the CNS during inflammation and neurodegeneration.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adult
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Aged
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Aged, 80 and over
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Astrocytes / physiology
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Excitatory Amino Acid Transporter 1 / genetics*
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Excitatory Amino Acid Transporter 1 / metabolism
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Excitatory Amino Acid Transporter 2
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Excitatory Amino Acid Transporter 3 / genetics*
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Excitatory Amino Acid Transporter 3 / metabolism
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Female
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Glutamate Plasma Membrane Transport Proteins / genetics*
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Glutamate Plasma Membrane Transport Proteins / metabolism
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Glutamic Acid / metabolism
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Humans
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Male
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Middle Aged
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Multiple Sclerosis / metabolism*
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Multiple Sclerosis / physiopathology*
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Nerve Degeneration / metabolism
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Nerve Degeneration / physiopathology
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Neurotoxins / metabolism
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Oligodendroglia / physiology
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Oligonucleotide Array Sequence Analysis
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Optic Nerve / metabolism
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Optic Nerve / physiopathology
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RNA, Messenger / analysis
Substances
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Excitatory Amino Acid Transporter 1
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Excitatory Amino Acid Transporter 2
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Excitatory Amino Acid Transporter 3
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Glutamate Plasma Membrane Transport Proteins
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Neurotoxins
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RNA, Messenger
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SLC1A1 protein, human
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SLC1A2 protein, human
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SLC1A3 protein, human
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Glutamic Acid