Cannabinoids, such as anandamide, are involved in pain transmission. We evaluated the effects of AM404 (N-(4-hydroxyphenyl)-5Z,8Z,11Z,14Z-eicosatetraenamide), an anandamide reuptake inhibitor, monitoring the expression of c-fos, a marker of activated neurons and the pain-related behaviours using formalin test. The study was carried out in an experimental model of inflammatory pain made by a single injection of formalin in rat hind paws. Formalin test showed that the antinociceptive effect of AM404 was evident in phase I. We found that Fos-positive neurons in dorsal superficial and deep laminae of the lumbar spinal cord increased in formalin-injected animals and that AM404 significantly reduced Fos induction. Co-administration of cannabinoid CB(1) receptor antagonist (AM251), cannabinoid CB(2) receptor antagonist (AM630) and transient receptor potential vanilloid type 1 (TRPV-1) antagonist (capsazepine), attenuate the inhibitory effect of AM404 and this effect was higher using cannabinoid CB(2) and vanilloid TRPV-1 receptor antagonists. These results suggest that AM404 could be a useful drug to reduce inflammatory pain in our experimental model and that cannabinoid CB(2) receptor and vanilloid TRPV-1 receptor, and to a lesser extent, the cannabinoid CB(1) receptor are involved.
|Titolo:||AM404 decreases Fos-immunoreactivity in the spinal cord in a model of inflammatory pain|
BIANCHI, ROSSELLA (Penultimo)
|Parole Chiave:||Anandamide; Cannabinoid receptor; Fos; Inflammatory pain; Spinal cord; TRPV-1 receptor|
|Data di pubblicazione:||4-giu-2007|
|Digital Object Identifier (DOI):||10.1016/j.brainres.2007.03.071|
|Appare nelle tipologie:||01 - Articolo su periodico|