title: Antinociceptive Effect of Najanalgesin from Naja Naja Atra in a Neuropathic Pain Model via Inhibition of c-Jun NH2-terminal Kinase.
abstract: BACKGROUND
  Najanalgesin, a toxin isolated from the venom of Naja naja atra, has been shown to exert significant analgesic effects in a neuropathic pain model in rats. However, the molecular mechanism underlying this protective effect of najanalgesin is poorly understood. The present study sought to evaluate the intracellular signaling pathways that are involved in the antinociceptive effect of najanalgesin on neuropathic pain.
  
  
  METHODS
  The antinociceptive properties of najanalgesin were tested in hind paw withdrawal thresholds in response to mechanical stimulation. We analyzed the participation of the mitogen-activated protein kinase p38, extracellular-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) by western blot analysis. This inhibition of JNK was confirmed by immunohistochemistry.
  
  
  RESULTS
  The phosphorylation levels of JNK (as well as its downstream molecule c-Jun), p38, and ERK were significantly increased after injury. Najanalgesin only inhibited JNK and c-Jun phosphorylation but had no effect on either ERK or p38. This inhibition of JNK was confirmed by immunohistochemistry, which suggested that the antinociceptive effect of najanalgesin on spinal nerve ligation-induced neuropathic pain in rats is associated with JNK activation in the spinal cord.
  
  
  CONCLUSIONS
  The antinociceptive effect of najanalgesin functions by inhibiting the JNK in a neuropathic pain model.
authors: Ying-Xia
authors: YX
authors: Liang
authors: Zhi-Yu
authors: ZY
authors: Zhang
authors: Department of Anesthesiology, Weifang Medical University, Weifang, Shandong 261053, China.
authors: Rui
authors: R
authors: Zhang
mesh_terms: D000818:Animals; D004546:Elapid Venoms / Q000627:therapeutic use*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009437:Neuralgia / Q000188:drug therapy* / Q000201:enzymology*; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D004546:Elapid Venoms; D016755:Proto-Oncogene Proteins c-jun; C543072:najanalgesin; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases