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Complex plastic changes in the neuropeptide Y system during ethanol intoxication and withdrawal in the rat brain

Authors

  • J.D. Olling,

    1. Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen and University Hospital Rigshospitalet 6102, Copenhagen, Denmark
    2. Department of Psychiatry, University Hospital Gentofte, Hellerup, Denmark
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  • J. Ulrichsen,

    1. Department of Psychiatry, University Hospital Gentofte, Hellerup, Denmark
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  • D.Z. Christensen,

    1. Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen and University Hospital Rigshospitalet 6102, Copenhagen, Denmark
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  • D.P.D. Woldbye

    Corresponding author
    1. Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen and University Hospital Rigshospitalet 6102, Copenhagen, Denmark
    • Laboratory of Neuropsychiatry, Department of Neuroscience and Pharmacology, University of Copenhagen and University Hospital Rigshospitalet 6102, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark
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Abstract

Previous studies show that chronic ethanol treatment induces prominent changes in brain neuropeptide Y (NPY). The purpose of the present study was to explore ethanol effects at a deeper NPY-system level, measuring expression of NPY and its receptors (Y1, Y2, Y5) as well as NPY receptor binding and NPY-stimulated [35S]GTPγS functional binding. Rats received intragastric ethanol repeatedly for 4 days, and the NPY system was studied in the hippocampal dentate gyrus (DG), CA3, CA1, and piriform cortex (PirCx) and neocortex (NeoCx) during intoxication, peak withdrawal (16 hr), late withdrawal (3 days), and 1 week after last ethanol administration. NPY mRNA levels decreased during intoxication and at 16 hr in hippocampal regions but increased in the PirCx and NeoCx at 16 hr. NPY mRNA levels were increased at 3 days and returned to control levels in most regions at 1 week. Substantial changes also occurred at the receptor level. Thus Y1, Y2, and Y5 mRNA labelling decreased at 16 hr in most regions, returning to control levels at 3 days, except for PirCx Y2 mRNA, which increased at 3 days and 1 week. Conversely, increases in NPY receptor binding occurred in hippocampal regions during intoxication and in functional binding in the DG and NeoCx during intoxication and at 16 hr and in PirCx during intoxication and at 1 week. Thus this study shows that ethanol intoxication and withdrawal induce complex plastic changes in the NPY system, with decreased/increased gene expression or binding occurring in a time- and region-specific manner. These changes may play an important role in mediating ethanol-induced changes in neuronal excitability. © 2009 Wiley-Liss, Inc.

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