Neuroscience 2004 Abstract
| Presentation Number: | 289.9 |
|---|---|
| Abstract Title: | p75 is expressed in CGRP immunoreactive primary afferents innervating the adult rat Conus medullaris. |
| Authors: |
Westerlund, U.*1
; Hoang, T. X.2
; Havton, L. A.2
1Dept fo Neurosurgery, Ins of Clin. Neurosci, Stockholm, Sweden 2CA, Section of Neurosurgery, SE-171 76, |
| Primary Theme and Topics |
Sensory Systems - Pain -- Spinal cord processing: anatomy and physiology |
| Session: |
289. Nociceptors and Growth Factors Poster |
| Presentation Time: | Sunday, October 24, 2004 1:00 PM-2:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # M8 |
| Keywords: | dorsal horn, dorsal rhizotomy, autonomic, confocal microscopy |
P75, a low affinity neurotrophic receptor, is expressed during development, in only specific motoneuron groups, and following injury in adult animals. In previous studies we have demonstrated that p75 immunoreactivity (IR) is associated with specific projections in the most lateral portion of the intermediolateral (IML) nucleus, as well as in the dorsal horn and commissure in the normal adult rat lumbosacral spinal cord (Westerlund et al., SfN abstract 497.16, 2003). We also showed that p75 expression in the lumbosacral cord was not altered after a mid-thoracic transection of the spinal cord, suggesting that the input source is not from the descending tracts. Here, we address whether the p75 IR is from the dorsal afferent roots and whether those dorsal fibers are associated with calcitonin gene-related peptide (CGRP) and substance P fibers. We performed a unilateral dorsal rhizotomy of the L4-S2 roots on adult male Sprague-Dawley rats and allowed a survival time of 5 days postoperatively. We performed immunohistochemistry for ChAT, p75, CGRP and substance P expression. In control animals, strong p75 expression was detected in Laminae I and II, the dorsal commissure and the lateral tract extending into the IML. Furthermore, confocal images showed co-localization of p75 and CGRP expression, but not with substance P expression in the dorsal horn. After unilateral dorsal root rhizotomies, both CGRP and p75 IR was undetectable in the dorsal horn and IML region of the lesioned side. Our studies suggest that the source of p75 IR in the dorsal horn of the adult spinal cord is from primary afferents and that p75 is associated with CGRP fibers.
Supported by NIH/NINDS (NS042719); Paralysis Project of America; State of California-Roman Reed Funds
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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