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Original Research ARTICLE

Front. Neural Circuits, 19 February 2013 | http://dx.doi.org/10.3389/fncir.2013.00022

Distribution and compartmental organization of GABAergic medium-sized spiny neurons in the mouse nucleus accumbens

  • 1CNRS, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France
  • 2Inserm, U661, Montpellier, France
  • 3Universités de Montpellier 1 & 2, UMR-5203, Montpellier, France
  • 4Laboratory of Neurophysiology, School of Medicine, Université Libre de Bruxelles, ULB Neuroscience Institute, Brussels, Belgium
  • 5CNRS, UMR-7224, Paris, France
  • 6Inserm, U952, Paris, France
  • 7Université Pierre et Marie Curie, UMR-7224, Paris, France
  • 8Laboratory of Systems Neuroscience, National Institute of Mental Health, Bethesda, MD, USA
  • 9Inserm, UMR-S 839, Paris, France
  • 10Université Pierre et Marie Curie, UMR-S 839, Paris, France
  • 11Institut du Fer á Moulin, Paris, France

The nucleus accumbens (NAc) is a critical brain region involved in many reward-related behaviors. The NAc comprises major compartments the core and the shell, which encompass several subterritories. GABAergic medium-sized spiny neurons (MSNs) constitute the output neurons of the NAc core and shell. While the functional organization of the NAc core outputs resembles the one described for the dorsal striatum, a simple classification of the NAc shell neurons has been difficult to define due to the complexity of the compartmental segregation of cells. We used a variety of BAC transgenic mice expressing enhanced green fluorescence (EGFP) or the Cre-recombinase (Cre) under the control of the promoter of dopamine D1, D2, and D3 receptors and of adenosine A2a receptor to dissect the microanatomy of the NAc. Moreover, using various immunological markers we characterized in detail the distribution of MSNs in the mouse NAc. In addition, cell-type specific extracellular signal-regulated kinase (ERK) phosphorylation in the NAc subterritories was analyzed following acute administration of SKF81297 (a D1R-like agonist), quinpirole (a D2 receptors (D2R)-like agonist), apomorphine (a non-selective DA receptor agonist), raclopride (a D2R-like antagonist), and psychostimulant drugs, including cocaine and d-amphetamine. Each drug generated a unique topography and cell-type specific activation of ERK in the NAc. Our results show the existence of marked differences in the receptor expression pattern and functional activation of MSNs within the shell subterritories. This study emphasizes the anatomical and functional heterogeneity of the NAc, which will have to be considered in its further study.

Keywords: medium-sized spiny neurons, BAC transgenic, nucleus accumbens, dopamine, psychostimulant, ERK signaling, neural circuits

Citation: Gangarossa G, Espallergues J, de Kerchove d'Exaerde A, El Mestikawy S, Gerfen CR, Hervé D, Girault J-A and Valjent E (2013) Distribution and compartmental organization of GABAergic medium-sized spiny neurons in the mouse nucleus accumbens. Front. Neural Circuits 7:22. doi: 10.3389/fncir.2013.00022

Received: 06 December 2012; Paper pending published: 28 December 2012;
Accepted: 02 February 2013; Published online: 19 February 2013.

Edited by:

Luis De Lecea, Stanford University, USA

Reviewed by:

Deborah Baro, Georgia State University, USA
Garret Stuber, University of North Carolina at Chapel Hill, USA
Marisela Morales, National Institute on Drug Abuse, National Institutes of Health, USA

Copyright © 2013 Gangarossa, Espallergues, de Kerchove d'Exaerde, El Mestikawy, Gerfen, Hervé, Girault and Valjent. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.

*Correspondence: Emmanuel Valjent, INSERM, U661, Universités de Montpellier 1 & 2, Montpellier, F-34094, France.
CNRS, UMR 5203, Institut de Génomique Fonctionnelle, Universités de Montpellier 1 & 2, 141 rue de la Cardonille, 34094 Montpellier, Cedex 05, France. e-mail: emmanuel.valjent@igf.cnrs.fr; emmanuel.valjent@gmail.com