Anatomical evidence that the uninjured adjacent L4 nerve plays a significant role in the development of peripheral neuropathic pain after L5 spinal nerve ligation in XXXX .

@entity35 @entity1931 @entity128 @entity158
UNASSIGNED: @entity35 develop @entity1931 and @entity1931 in the hind paw after L5 spinal nerve ligation. Phosphorylated Extracellular Regulated Kinase (pERK) was used as a @entity158 marker to investigate the potential role of adjacent uninjured L4 nerve in the development of @entity1931 after @entity128 . Left L5 nerve was ligated and sectioned in @entity35 . Three days later, @entity35 were randomly assigned into 5 groups; each had both hind paws immersed in water at different temperatures (no heat, 37, 42, 47 and 52   C) under sevoflurane anesthesia for 2 minutes. Five minutes after stimulation, the @entity35 were sacrificed and sections of L3-L6 spinal segments were stained immunocytochemically with pERK antibody. pERK immunoreactivity, which is not detectable in the normal spinal cord, was discernible in neurons (not glia) of the superficial dorsal horn after noxious heat stimuli. pERK positive neurons clearly overlapped in lamiae I-II with normal unmyelinated, and thin myelinated afferents labeled with calcitonin gene related peptide and isolectin B4, and injured unmyelinated afferents labeled with vasoactive intestinal polypeptide. There was a linear increase in pERK immunoreactivity on both sides with increase in temperature. Importantly, the number of positive pERK neurons was significantly higher in the ipsilateral side of L4 spinal segment, which receives innervation from uninjured L4 nerve, compared with contralateral control side which receives both uninjured L4 and L5 spinal nerves. The data demonstrate that the uninjured L4 nerve plays an important role in the development of @entity1931 at the spinal cord level after @entity128 . This article is protected by copyright. All rights reserved.
