NMDA receptor antagonists attenuate mechanical hyperalgesia in rats with unilateral inflammation of the hindpaw

Neurosci Lett. 1993 Nov 26;163(1):22-6. doi: 10.1016/0304-3940(93)90220-f.


The effects of N-methyl-D-aspartate (NMDA) receptor antagonists on mechanical hyperalgesia associated with tissue inflammation were studied. Following an injection of the inflammatory agent, complete Freund's adjuvant, into the rat hindpaw, there was a significant decrease in threshold and an increase in response duration to mechanical stimuli, suggesting that a state of mechanical hyperalgesia was induced. The intrathecal administration of the NMDA receptor antagonists, dizocilpine maleate and (+/-)-2-amino-5-phosphonopentanoic acid, significantly increased mechanical threshold and reduced response duration in the inflamed hindpaw, but had no effect on the non-injected paw. The results suggest that NMDA receptor activation may contribute to the mechanical hyperalgesia that follows peripheral tissue inflammation.

MeSH terms

  • 2-Amino-5-phosphonovalerate / administration & dosage
  • 2-Amino-5-phosphonovalerate / pharmacology
  • Animals
  • Dizocilpine Maleate / administration & dosage
  • Dizocilpine Maleate / pharmacology
  • Freund's Adjuvant
  • Inflammation / chemically induced
  • Inflammation / physiopathology*
  • Injections, Spinal
  • Male
  • Mechanoreceptors / drug effects
  • Pain Measurement / drug effects*
  • Pain Threshold / drug effects
  • Physical Stimulation
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors*


  • Receptors, N-Methyl-D-Aspartate
  • Dizocilpine Maleate
  • 2-Amino-5-phosphonovalerate
  • Freund's Adjuvant