title: Extracellular signal-regulated kinase mitogen-activated protein kinase activation in the dorsal root ganglion (DRG) and spinal cord after DRG injury in rats.
abstract: METHODS
  We investigated the extracellular signal-regulated kinase (ERK) activation by immunohistochemically detecting phosphorylated ERK (pERK) in the dorsal root ganglion (DRG) and spinal cord.
  
  
  OBJECTIVE
  To clarify the ERK activation in the rat nervous system following DRG injury.
  
  
  BACKGROUND
  Radicular pain is known to be associated with DRG injury caused by intervertebral disc herniation. ERK is activated by phosphorylation in the DRG and spinal cord by noxious stimuli, which are related to pain hypersensitivity.
  
  
  METHODS
  From 2 minutes to 24 hours after the left L4 DRG crush injury, L4 DRGs and spinal cords were resected to prepare serial sections, which were investigated immunohistochemically.
  
  
  RESULTS
  In the DRG, ERK activation was detected in neurons and satellite cells at 2 minutes; the former was maintained at increased levels for 20 minutes, and the latter for 4 hours. At 30 minutes, pERK immunoreactivity was observed in Schwann cells, which continued for up to 24 hours. In the spinal cord, pERK-positive neurons were detected at 2 minutes, and the pERK levels were maintained at increased levels for 20 minutes.
  
  
  CONCLUSIONS
  Profiles of pERK induction in neurons after DRG injury were similar between the DRG and spinal cord, whereas pERK induction in the satellite cells was more long lasting. The pERK induction in Schwann cells in the DRG was late onset and the most long lasting.
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. dowya@graduate.chiba-u.jp
authors.forename: Hideo
authors.initials: H
authors.lastname: Doya
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Aoki
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ino
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Hideshige
authors.initials: H
authors.lastname: Moriya
authors.forename: Toshihide
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000201:enzymology* / Q000293:injuries*; D007150:Immunohistochemistry; D008159:Lumbar Vertebrae; D008297:Male; D009409:Nerve Crush; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000201:enzymology*; D013997:Time Factors; D014949:Wounds, Nonpenetrating / Q000201:enzymology*
chemical_list: D048049:Extracellular Signal-Regulated MAP Kinases