Get access

Axonal projections originating from raphe serotonergic neurons in the developing and adult zebrafish, Danio rerio, using transgenics to visualize raphe-specific pet1 expression

Authors

  • Christina Lillesaar,

    Corresponding author
    1. HelmholtzZentrum München, German Research Center for Environmental Health, Department of Zebrafish Neurogenetics, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
    • Zebrafish Neurogenetics, Institute of Developmental Genetics, HelmholtzZentrum Muenchen, German Research Center for Environmental Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Germany
    Search for more papers by this author
  • Christian Stigloher,

    1. HelmholtzZentrum München, German Research Center for Environmental Health, Department of Zebrafish Neurogenetics, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
    Search for more papers by this author
  • Birgit Tannhäuser,

    1. HelmholtzZentrum München, German Research Center for Environmental Health, Department of Zebrafish Neurogenetics, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
    Search for more papers by this author
  • Mario F. Wullimann,

    1. Department of Biology II, Division of Neurobiology, Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University (LMU) Munich, D-82152 Planegg-Martinsried, Germany
    Search for more papers by this author
  • Laure Bally-Cuif

    Corresponding author
    1. HelmholtzZentrum München, German Research Center for Environmental Health, Department of Zebrafish Neurogenetics, Institute of Developmental Genetics, D-85764 Neuherberg, Germany
    • Zebrafish Neurogenetics, Institute of Developmental Genetics, HelmholtzZentrum Muenchen, German Research Center for Environmental Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg, Germany
    Search for more papers by this author

Abstract

Serotonin is a major central nervous modulator of physiology and behavior and plays fundamental roles during development and plasticity of the vertebrate central nervous system (CNS). Understanding the developmental control and functions of serotonergic neurons is therefore an important task. In all vertebrates, prominent serotonergic neurons are found in the superior and inferior raphe nuclei in the hindbrain innervating most CNS regions. In addition, all vertebrates except for mammals harbor other serotonergic centers, including several populations in the diencephalon. This, in combination with the intricate and wide distribution of serotonergic fibers, makes it difficult to sort out serotonergic innervation originating from the raphe from that of other serotonergic cell populations. To resolve this issue, we isolated the regulatory elements of the zebrafish raphe-specific gene pet1 and used them to drive expression of an eGFP transgene in the raphe population of serotonergic neurons. With this approach together with retrograde tracing we 1) describe in detail the development, anatomical organization, and projection pattern of zebrafish pet1-positive neurons compared with their mammalian counterparts, 2) identify a new serotonergic population in the ventrolateral zebrafish hindbrain, and 3) reveal some extent of functional subdivisions within the zebrafish superior raphe complex. Together, our results reveal for the first time the specific innervation pattern of the zebrafish raphe and, thus, provide a new model and various tools to investigate further the role of raphe serotonergic neurons in vertebrates. J. Comp. Neurol. 512:158–182, 2009. © 2008 Wiley-Liss, Inc.

Get access to the full text of this article

Ancillary