Actions of N-arachidonyl-glycine in a rat inflammatory pain model.
BACKGROUND
While cannabinoid receptor agonists have analgesic activity in inflammatory pain states they produce a range of side effects. Recently, it has been demonstrated that the arachidonic acid-amino acid conjugate, N-arachidonyl-glycine (NA-glycine) is effective in acute pain models.


RESULTS
In the present study we examined the effect of NA-glycine in a rat model of inflammatory pain. Intrathecal administration of NA-glycine (70 - 700 nmol) and the pan-cannabinoid receptor agonist HU-210 (10 nmol) reduced the mechanical allodynia and thermal hyperalgesia induced by intraplantar injection of Freund's complete adjuvant (FCA). The actions of HU-210, but not NA-glycine were reduced by the cannabinoid CB1 receptor antagonist AM251. The cannabinoid CB2 receptor antagonist SR144528 also had no effect on the actions of NA-glycine. In contrast, N-arachidonyl-GABA (NA-GABA, 700 nmol) and N-arachidonyl-alanine (NA-alanine, 700 nmol) had no effect on allodynia and hyperalgesia. HU-210, but not NA-glycine produced a reduction in rotarod latency.


CONCLUSIONS
These findings suggest that NA-glycine may provide a novel non-cannabinoid receptor mediated approach to alleviate inflammatory pain.
Succar
Rebecca
R
Pain Management Research Institute, Northern Clinical School, The University of Sydney at Royal North Shore Hospital, St Leonards, 2065, NSW, Australia. rebeccas@med.usyd.edu.au
Mitchell
Vanessa A
VA
Vaughan
Christopher W
CW
D000818:Animals; D001095:Arachidonic Acids / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D063386:Cannabinoid Receptor Agonists; D004195:Disease Models, Animal; D005998:Glycine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D007249:Inflammation / Q000188:drug therapy*; D007278:Injections, Spinal; D008297:Male; D010146:Pain / Q000188:drug therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time
D001095:Arachidonic Acids; D063386:Cannabinoid Receptor Agonists; C465623:N-arachidonylglycine; D005998:Glycine