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Expression of mRNA for neurotrophic factors and their receptors in the rat dorsal root ganglion and sciatic nerve following nerve injury
Author(s) -
Sebert M. E.,
Shooter E. M.
Publication year - 1993
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490360402
Subject(s) - dorsal root ganglion , sciatic nerve , ganglion , dorsum , nerve injury , sciatic nerve injury , anatomy , neurotrophin , medicine , receptor , neurotrophic factors , anesthesia , neuroscience , chemistry , biology
Abstract The adult rat dorsal root ganglion (DRG) produces mRNA for the neurotrophic factors nerve growth factor (NGF) and brain‐derived neurotrophic factor (BDNF) and contains large populations of neurons responsive to these factors. We report that following a focal crush injury of the sciatic nerve, NGF mRNA expression increases threefold and BDNF mRNA twofold, in the ipsilateral L4 and L5 DRGs. The mRNAs encoding the cognate neurotrophin receptors, p75 NGFR , trkA, and trkB were expressed in the DRG throughout the post‐injury time course, suggesting that DRG neurons remain responsive to both NGF and BDNF. p75 NGFR mRNA levels became transiently depressed in the DRG during the first several days after the lesion but returned to normal within 1 week. trk B mRNA was expressed in the normal sciatic nerve and levels were not altered by nerve crush. RNase protection assays detected both full‐length and truncated trk B transcripts in the DRG, but only truncated trk B mRNA, lacking the tyrosine kinase domain, was detected in the sciatic nerve. Likewise, trk A transcripts were not detected by RNase protection in normal sciatic nerve or in a segment of nerve distal to the crush site. These results are consistent with a model in which regenerating sensory neurons are supported by neurotrophic factors synthesized within the DRG. © 1993 Wiley‐Liss, Inc.