Abstract
In order to approach the astroglial implication of addictive and neurotoxic processes associated with psychostimulant drug abuse, the effects of amphetamine or cocaine (1-100 microM) on redox status, AP-1 transcription factor and pro-enkephalin, an AP-1 target gene, were investigated in the human astrocyte-like U373 MG cells. We demonstrated an early increase in the generation of radical oxygen species and in the formation of 4-hydroxynonenal-adducts reflecting the pro-oxidant action of both substances. After 1 h or 96 h of treatment, Fos and Jun protein levels were altered and the DNA-binding activity of AP-1 was increased in response to both substances. Using supershift experiments, we observed that the composition of AP-1 dimer differed according to the substance and the duration of treatment. FRA-2 protein represented the main component of the chronic amphetamine- or cocaine-activated complexes, which suggests its relevance in the long-term effects of psychostimulant drugs. Concomitantly, the pro-enkephalin gene was differently regulated by either 6 h or 96 h of treatment. Because astrocytes interact extensively with the neurons in the brain, our data led us to conclude that oxidation-regulated AP-1 target genes may represent one of the molecular mechanisms underlying neuronal adaptation associated with psychostimulant dependence.
MeSH terms
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Amino Acid Transport System X-AG / genetics
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Amino Acid Transport System X-AG / metabolism
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Amphetamine / pharmacology*
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Analysis of Variance
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Astrocytes / drug effects*
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Blotting, Western / methods
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Cell Line
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Central Nervous System Agents / pharmacology*
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Cocaine / pharmacology*
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DNA-Binding Proteins / metabolism
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Dose-Response Relationship, Drug
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Drug Administration Schedule
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Electrophoretic Mobility Shift Assay / methods
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Enkephalins / genetics
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Enkephalins / metabolism*
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Excitatory Amino Acid Transporter 2 / genetics
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Excitatory Amino Acid Transporter 2 / metabolism
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Fluoresceins
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Fos-Related Antigen-2
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Gene Expression Regulation / drug effects
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Glial Fibrillary Acidic Protein / metabolism
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Humans
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Oxidation-Reduction / drug effects
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Protein Precursors / genetics
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Protein Precursors / metabolism*
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Proto-Oncogene Proteins c-fos / metabolism
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Proto-Oncogene Proteins c-jun / metabolism
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RNA, Messenger / metabolism
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Reactive Oxygen Species / metabolism
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Reverse Transcriptase Polymerase Chain Reaction / methods
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Tetrazolium Salts
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Thiazoles
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Time Factors
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Transcription Factor AP-1 / metabolism*
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Transcription Factors / metabolism
Substances
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Amino Acid Transport System X-AG
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Central Nervous System Agents
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DNA-Binding Proteins
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Enkephalins
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Excitatory Amino Acid Transporter 2
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FOSL2 protein, human
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Fluoresceins
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Fos-Related Antigen-2
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Glial Fibrillary Acidic Protein
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Protein Precursors
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Proto-Oncogene Proteins c-fos
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Proto-Oncogene Proteins c-jun
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RNA, Messenger
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Reactive Oxygen Species
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Tetrazolium Salts
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Thiazoles
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Transcription Factor AP-1
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Transcription Factors
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fos-related antigen 1
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proenkephalin
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diacetyldichlorofluorescein
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Amphetamine
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thiazolyl blue
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Cocaine