Expression of vesicular glutamate transporters 1 and 2 in the cells of origin of the rat thalamostriatal pathway

J Chem Neuroanat. 2008 Jan;35(1):101-7. doi: 10.1016/j.jchemneu.2007.08.001. Epub 2007 Aug 8.

Abstract

The present study is focused on the analysis of the vesicular glutamate transporters 1 and 2 (VGLUT1 and VGLUT2) used by thalamic neurons giving rise to the thalamostriatal system. Instead of studying the distribution of VGLUT proteins at the level of thalamostriatal terminals, this report is focused on identifying the expression of the VGLUT mRNAs within the parent cell bodies of thalamic neurons innervating the striatum. For this purpose, we have combined dual in situ hybridization to detect both VGLUT1 and VGLUT2 mRNAs together with retrograde tracing with cholera toxin. Our results show that VGLUT2 is the only vesicular glutamate transporter expressed in thalamostriatal-projecting neurons located in the midline and intralaminar nuclei, whereas all neurons from the ventral thalamic nuclei innervating the striatum express both VGLUTs, at least at the mRNA level. Indeed, the mRNAs encoding for VGLUT1 and VGLUT2 displayed a sharp complementary subcellular distribution within neurons from the ventral thalamic nuclei giving rise to thalamostriatal projections. The differential distribution of VGLUT mRNAs lead us to conclude that the thalamostriatal pathway is a dual system, composed by a preponderant projection arising from the midline and intralaminar nuclei using VGLUT2 as the glutamate transporter, together with another important source of striatal afferents arising from neurons in the ventral thalamic relay nuclei containing both kinds of vesicular glutamate transporters.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Mapping
  • Cholera Toxin / metabolism
  • Corpus Striatum / cytology
  • Corpus Striatum / metabolism*
  • Glutamic Acid / metabolism*
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Intralaminar Thalamic Nuclei / cytology
  • Intralaminar Thalamic Nuclei / metabolism
  • Male
  • Midline Thalamic Nuclei / cytology
  • Midline Thalamic Nuclei / metabolism
  • Neural Pathways / cytology
  • Neural Pathways / metabolism
  • RNA, Messenger / analysis
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Staining and Labeling
  • Synaptic Transmission / physiology
  • Thalamus / cytology
  • Thalamus / metabolism*
  • Vesicular Glutamate Transport Protein 1 / genetics*
  • Vesicular Glutamate Transport Protein 2 / genetics*

Substances

  • RNA, Messenger
  • Slc17a6 protein, rat
  • Slc17a7 protein, rat
  • Vesicular Glutamate Transport Protein 1
  • Vesicular Glutamate Transport Protein 2
  • Glutamic Acid
  • Cholera Toxin