Rapid Temporal Changes in the Expression of a Set of Neuromodulatory Genes During Alcohol Withdrawal in the Dorsal Vagal Complex: Molecular Evidence of Homeostatic Disturbance

Authors

  • Kate Freeman,

    1. Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
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  • Mary M. Staehle,

    1. Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
    2. Department of Chemical Engineering, Rowan University, Glassboro, New Jerasey
    3. Department of Chemical Engineering, University of Delaware, Newark, Delaware
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  • Zeynep H. Gümüş,

    1. Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, New York
    2. HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, New York
    3. Cancer Center, Weill Medical College of Cornell University, New York, New York
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  • Rajanikanth Vadigepalli,

    1. Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
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  • Gregory E. Gonye,

    1. Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
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  • Carmen N. Nichols,

    1. Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
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  • Babatunde A. Ogunnaike,

    1. Department of Chemical Engineering, University of Delaware, Newark, Delaware
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  • Jan B. Hoek,

    1. Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
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  • James S. Schwaber

    Corresponding author
    • Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, Pennsylvania
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  • The first two authors contributed equally to this work.

Reprint requests: James S. Schwaber, PhD, Department of Pathology, Anatomy and Cell Biology, Daniel Baugh Institute for Functional Genomics and Computational Biology, Thomas Jefferson University Philadelphia, Philadelphia, PA 19107; Tel.: 215-503-7823; Fax: 215-503-2636; E-mail: schwaber@mail.dbi.tju.edu

Abstract

Background

Chronic alcohol exposure produces neuroadaptation, which increases the risk of cellular excitotoxicity and autonomic dysfunction during withdrawal. The temporal progression and regulation of the gene expression that contributes to this physiologic and behavioral phenotype is poorly understood early in the withdrawal period. Further, it is unexplored in the dorsal vagal complex (DVC), a brainstem autonomic regulatory structure.

Methods

We use a quantitative polymerase chain reaction platform to precisely and simultaneously measure the expression of 145 neuromodulatory genes in more than 100 rat DVC samples from control, chronically alcohol-exposed, and withdrawn rats. To gain insight into the dynamic progression and regulation of withdrawal, we focus on the expression of a subset of functionally relevant genes during the first 48 hours, when behavioral symptoms are most severe.

Results

In the DVC, expression of this gene subset is essentially normal in chronically alcohol-exposed rats. However, withdrawal results in rapid, large-magnitude expression changes in this group. We observed differential regulation in 86 of the 145 genes measured (59%), some as early as 4 hours into withdrawal. Time series measurements (4, 8, 18, 32, and 48 hours after alcohol removal) revealed dynamic expression responses in immediate early genes, γ-aminobutyric acid type A, ionotropic glutamate, and G-protein coupled receptors and the Ras/Raf signaling pathway. Together, these changes elucidate a complex, temporally coordinated response that involves correlated expression of many functionally related groups. In particular, the expression patterns of Gabra1, Grin2a, Grin3a, and Grik3 were tightly correlated. These receptor subunits share overrepresented transcription factor binding sites for Pax-8 and other transcription factors, suggesting a common regulatory mechanism and a role for these transcription factors in the regulation of neurotransmission within the first 48 hours of alcohol withdrawal.

Conclusions

Expression in this gene set is essentially normal in the alcohol-adapted DVC, but withdrawal results in immediate, large-magnitude, and dynamic changes. These data support both increased research focus on the biological ramifications of alcohol withdrawal and enable novel insights into the dynamic withdrawal expression response in this understudied homeostatic control center.

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