Pharmacological recruitment of the GABAergic tail of the ventral tegmental area by acute drug exposure

Authors

  • Jennifer Kaufling,

    1. Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
    2. Université de Strasbourg, Strasbourg, France
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  • Elisabeth Waltisperger,

    1. Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
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  • Romain Bourdy,

    1. Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
    2. Université de Strasbourg, Strasbourg, France
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  • Antoine Valera,

    1. Université de Strasbourg, Strasbourg, France
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  • Pierre Veinante,

    1. Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
    2. Université de Strasbourg, Strasbourg, France
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  • Marie-José Freund-Mercier,

    1. Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
    2. Université de Strasbourg, Strasbourg, France
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  • Michel Barrot

    Corresponding author
    1. Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
      Dr Michel Barrot, Institut des Neurosciences Cellulaires et Intégratives, 21 rue René Descartes, 67084 Strasbourg Cedex, France. E-mail: mbarrot@inci-cnrs.unistra.fr
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Dr Michel Barrot, Institut des Neurosciences Cellulaires et Intégratives, 21 rue René Descartes, 67084 Strasbourg Cedex, France. E-mail: mbarrot@inci-cnrs.unistra.fr

Abstract

BACKGROUND AND PURPOSE The tail of the ventral tegmental area (tVTA), also called the rostromedial tegmental nucleus, is a newly defined brain structure and a potential control centre for dopaminergic activity. It was identified by the induction of DeltaFosB following chronic cocaine exposure. In this work, we screened 20 drugs for their ability to induce FosB/DeltaFosB in the tVTA.

EXPERIMENTAL APPROACH Immunohistochemistry following systemic drug administration was used to study FosB/DeltaFosB induction in the tVTA of adult rats. Double-staining was used to determine whether dopamine or GABA neurones are involved in this induction.

KEY RESULTS The acute injection of the psychostimulant drugs cocaine, D-amphetamine, (+/−)-3,4-methylenedioxymethamphetamine (MDMA), methylphenidate or caffeine, induced the expression of FosB/DeltaFosB in the tVTA GABAergic cells. No induction was observed following exposure to ethanol, diazepam, γ-hydroxybutyric acid (GHB), morphine, ketamine, phencyclidine (PCP), Δ9-tetrahydrocannabinol (THC), sodium valproic acid or gabapentin. To evaluate the role of monoamine transporters in the psychostimulant-induced expression of FosB/DeltaFosB, we tested the antidepressant drugs reboxetine, nortriptyline, fluoxetine and venlafaxine (which target the noradrenaline and/or the 5-hydroxytryptamine transporters), the 5-hydroxytryptamine releasing agent dexfenfluramine, and the dopamine transporter inhibitor GBR12909. Only GBR12909 was able to induce FosB/DeltaFosB expression in the tVTA, showing that this induction is mediated by dopamine.

CONCLUSIONS AND IMPLICATIONS Newly described brain structures may help to increase our knowledge of brain function, pathology and targets for treatments. FosB/DeltaFosB induction in the tVTA is a common feature of drugs sharing psychostimulant properties but not of drugs sharing risk of abuse.

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