Abstract
The ability of cocaine to produce lasting neural adaptations in mesocorticolimbic brain regions is thought to promote drug seeking and facilitate addiction in humans. The Ras-controlled Raf-MEK-ERK protein kinase signaling cascade has been implicated in the behavioral and neurobiological actions of cocaine in animals. However, these pharmacological studies have not been able to determine the specific role of the two predominant isoforms of ERK (ERK1 and ERK2) in these processes. We report here that deletion of the ERK1 isoform, which leads to increased ERK2 stimulus-dependent signaling, facilitates the development of cocaine-induced psychomotor sensitization and the acquisition of a cocaine conditioned place preference. Conversely, pharmacological blockade of ERK signaling attenuates the development of psychomotor sensitization to cocaine. Finally, cocaine-evoked gene expression in mesocorticolimbic brain regions is potentiated in ERK1-deficient mice. Thus, alterations in ERK signaling influence both the neurobiological impact of cocaine and its ability to produce enduring forms of drug experience-dependent behavioral plasticity. Our results suggest that enhanced ERK2 signaling following repeated drug exposure may facilitate the development of forms of cocaine-induced plasticity that contribute to addiction.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Behavior, Animal / drug effects*
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Behavior, Animal / physiology
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Brain / drug effects*
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Brain / metabolism
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Brain / physiopathology
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Cocaine / adverse effects*
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Cocaine-Related Disorders / enzymology
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Cocaine-Related Disorders / genetics*
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Cocaine-Related Disorders / physiopathology
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Conditioning, Psychological / drug effects
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Conditioning, Psychological / physiology
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Corpus Striatum / drug effects
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Corpus Striatum / enzymology
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Corpus Striatum / physiopathology
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Disease Models, Animal
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Dopamine Uptake Inhibitors / adverse effects
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Enkephalins / metabolism
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Enzyme Inhibitors / pharmacology
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Gene Expression Regulation, Enzymologic / drug effects
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Gene Expression Regulation, Enzymologic / physiology
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Genes, Immediate-Early / drug effects*
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Genes, Immediate-Early / genetics
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Limbic System / drug effects
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Limbic System / enzymology
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Limbic System / physiopathology
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MAP Kinase Signaling System / drug effects
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MAP Kinase Signaling System / genetics
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Male
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3 / genetics*
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Proto-Oncogene Proteins c-fos / drug effects
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Proto-Oncogene Proteins c-fos / genetics
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Ventral Tegmental Area / drug effects
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Ventral Tegmental Area / enzymology
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Ventral Tegmental Area / physiopathology
Substances
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Dopamine Uptake Inhibitors
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Enkephalins
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Enzyme Inhibitors
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Proto-Oncogene Proteins c-fos
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Cocaine