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

• DOI: 10.1046/j.1460-9568.2003.02406.x
• Publication Date: 2003-03-06T14:50:01Z
• Authors: A. J. Todd; D. I. Hughes; E. Polgár; G. G. Nagy; M. Mackie; O. P. Ottersen; D. J. Maxwell
• Keywords: Male; Afferent Pathways; Cholera Toxin; 0303 health sciences; Microscopy, Confocal; Lumbosacral Region; Presynaptic Terminals; Fluorescent Antibody Technique; Gene Expression; Membrane Transport Proteins; Orvostudományok; Enkephalins; Axons; Rats; Posterior Horn Cells; Microscopy, Electron; 03 medical and health sciences; Adjuvants, Immunologic; Interneurons; Animals; Elméleti orvostudományok; Rats, Wistar; Carrier Proteins; Neurotensin

Abstract Two vesicular glutamate transporters, VGLUT1 and VGLUT2, have recently been identified, it has reported that they are expressed by largely nonoverlapping populations of glutamatergic neurons in the brain. We used immunocytochemistry with antibodies against both together markers for various spinal neurons, an attempt to identify interneurons dorsal horn mid‐lumbar cord rat. The great majority (94–100%) nonprimary axonal boutons contained somatostatin, substance P or neurotensin, as well 85% those enkephalin, were VGLUT2‐immunoreactive, which suggests most synthesize these peptides glutamatergic. In support this, we found somatostatin‐ enkephalin‐containing (including somatostatin‐immunoreactive lacked calcitonin gene‐related peptide therefore probably derived from local interneurons) formed synapses at AMPA receptors present. also investigated VGLUT expression central terminals primary afferents. Myelinated afferents identified cholera toxin B subunit; lamina I whereas all deeper laminae VGLUT1‐immunoreactive, some (in III–VI) appeared contain transporters. However, peptidergic somatostatin (most unmyelinated), nonpeptidergic C fibres (identified Bandeiraea simplicifolia isolectin B4) showed low levels VGLUT2‐immunoreactivity, not immunoreactive either antibody. As thought be glutamatergic, this raises possibility unmyelinated afferents, nociceptors, express a different transporter.