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Attenuation and recovery of nerve growth factor receptor mRNA in dorsal root ganglion neurons following axotomy
Author(s) -
Krekoski C. A.,
Parhad I. M.,
Clark A. W.
Publication year - 1996
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.490430102
Subject(s) - axotomy , trk receptor , dorsal root ganglion , nerve growth factor , low affinity nerve growth factor receptor , tropomyosin receptor kinase a , medicine , sciatic nerve , endocrinology , biology , neuroscience , receptor , central nervous system , spinal cord
The actions of nerve growth factor (NGF) are mediated by two receptor proteins, trk and p75. Recent evidence indicates that NGF upregulates the expression of both trk and p75 in responsive neurons including rat dorsal root ganglion (DRG) neurons. Axotomy by disconnecting the neuron from its source of target‐derived NGF is predicted to lead to the downregulation of trk and p75 expression. However, previous studies of the effects of axotomy on trk and p75 mRNA expression in rat DRG have yielded discrepant results. We report that following sciatic nerve crush, trk and p75 mRNA levels in L4‐L6 DRG decrease to ∼50% of control levels at 4–14 days, return to control levels by 30 days, and are increased by ∼30% at 60 days. Similar changes are observed following nerve transection although mRNA levels are slower in returning to normal and do not exceed control levels at later timepoints. Thus, trk and p75 expression decline early following target disconnection and later recover irrespective of target reinnervation. These observations indicate that target derived NGF is required for the maintenance of NGF receptor expression in adult rat DRG neurons and that non‐target derived factors can appropriate this function following peripheral nerve injury. © 1996 Wiley‐Liss, Inc.