Dr. Judy L. Morris is a Principal Research Fellow of the National Health and Medical Research Council of Australia.
Most peptide-containing sensory neurons lack proteins for exocytotic release and vesicular transport of glutamate
Article first published online: 25 JAN 2005
Copyright © 2005 Wiley-Liss, Inc.
Journal of Comparative Neurology
Volume 483, Issue 1, pages 1–16, 28 February 2005
How to Cite
Morris, J. L., König, P., Shimizu, T., Jobling, P. and Gibbins, I. L. (2005), Most peptide-containing sensory neurons lack proteins for exocytotic release and vesicular transport of glutamate. J. Comp. Neurol., 483: 1–16. doi: 10.1002/cne.20399
- Issue published online: 25 JAN 2005
- Article first published online: 25 JAN 2005
- Manuscript Accepted: 6 SEP 2004
- Manuscript Revised: 31 AUG 2004
- Manuscript Received: 31 MAY 2004
- National Health & Medical Research Council of Australia. Grant Numbers: 000023, 000027, 160083
- SNARE proteins;
- vesicular glutamate transporters;
- substance P;
- calcitonin gene-related peptide (CGRP);
- nociceptive neurons;
- spinal cord
We used multiple-labeling immunohistochemistry and confocal microscopy to examine co-expression of immunoreactivity for vesicular glutamate transporters (VGluTs), synaptic vesicle proteins, and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins in peptide-containing sensory neurons of guinea pigs, mice, and toads. Axon terminals in the superficial layers of the dorsal horn of the spinal cord with immunoreactivity (IR) for both substance P (SP) and calcitonin gene-related peptide (CGRP) lacked IR for synaptosome-associated protein of 25 kDa (SNAP-25), syntaxin, synaptotagmin, synaptophysin, and synapsin, although adjacent varicosities without neuropeptides had IR for these synaptic proteins. Similarly, peptide-containing axon terminals in the superficial dorsal horn lacked IR for VGluT1 and VGluT2, despite the presence of VGluT2-IR in nearby nonpeptide varicosities. VGluT3-IR was sparse in the dorsal horn of the mouse spinal cord and was not present in peptide-containing axons. Most peripheral terminals of sensory neurons with both SP-IR and CGRP-IR in the skin, viscera, and autonomic ganglia of guinea pigs and mice also lacked IR for synaptic vesicle proteins, SNARE proteins, VGluT1, and VGluT2. In dorsal root ganglia from guinea pigs and mice, most small neurons with IR for both SP and CGRP lacked IR for SNAP-25, VGluT1, and VGluT2. Thus, proteins considered essential for vesicular uptake and exocytotic release of glutamate are not expressed at detectable levels by most sensory neurons containing SP and CGRP in rodents and toads. These data raise the possibility that most peptide-containing sensory neurons may not normally release glutamate as a transmitter. J. Comp. Neurol. 483:1–16, 2005. © 2005 Wiley-Liss, Inc.