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The expression of vesicular glutamate transporters VGLUT1 and VGLUT2 in neurochemically defined axonal populations in the rat spinal cord with emphasis on the dorsal horn.
- Source :
-
The European journal of neuroscience [Eur J Neurosci] 2003 Jan; Vol. 17 (1), pp. 13-27. - Publication Year :
- 2003
-
Abstract
- Two vesicular glutamate transporters, VGLUT1 and VGLUT2, have recently been identified, and it has been reported that they are expressed by largely nonoverlapping populations of glutamatergic neurons in the brain. We have used immunocytochemistry with antibodies against both transporters, together with markers for various populations of spinal neurons, in an attempt to identify glutamatergic interneurons in the dorsal horn of the mid-lumbar spinal cord of the rat. The great majority (94-100%) of nonprimary axonal boutons that contained somatostatin, substance P or neurotensin, as well as 85% of those that contained enkephalin, were VGLUT2-immunoreactive, which suggests that most dorsal horn neurons that synthesize these peptides are glutamatergic. In support of this, we found that most somatostatin- and enkephalin-containing boutons (including somatostatin-immunoreactive boutons that lacked calcitonin gene-related peptide and were therefore probably derived from local interneurons) formed synapses at which AMPA receptors were present. We also investigated VGLUT expression in central terminals of primary afferents. Myelinated afferents were identified with cholera toxin B subunit; most of those in lamina I were VGLUT2-immunoreactive, whereas all those in deeper laminae were VGLUT1-immunoreactive, and some (in laminae III-VI) appeared to contain both transporters. However, peptidergic primary afferents that contained substance P or somatostatin (most of which are unmyelinated), as well as nonpeptidergic C fibres (identified with Bandeiraea simplicifolia isolectin B4) showed low levels of VGLUT2-immunoreactivity, or were not immunoreactive with either VGLUT antibody. As all primary afferents are thought to be glutamatergic, this raises the possibility that unmyelinated afferents, most of which are nociceptors, express a different vesicular glutamate transporter.
- Subjects :
- Adjuvants, Immunologic analysis
Animals
Cholera Toxin analysis
Enkephalins analysis
Fluorescent Antibody Technique
Gene Expression
Interneurons chemistry
Lumbosacral Region
Male
Microscopy, Confocal
Microscopy, Electron
Neurotensin analysis
Presynaptic Terminals chemistry
Rats
Rats, Wistar
Receptors, AMPA analysis
Receptors, AMPA ultrastructure
Somatostatin analysis
Substance P analysis
Synapses ultrastructure
Vesicular Glutamate Transport Protein 1
Vesicular Glutamate Transport Protein 2
Afferent Pathways chemistry
Axons chemistry
Carrier Proteins analysis
Membrane Transport Proteins
Posterior Horn Cells chemistry
Spinal Cord chemistry
Vesicular Transport Proteins
Subjects
Details
- Language :
- English
- ISSN :
- 0953-816X
- Volume :
- 17
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The European journal of neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 12534965
- Full Text :
- https://doi.org/10.1046/j.1460-9568.2003.02406.x