“The hypothesis was tested that THC and anandamide elicit antinociception in the paw pressure test, and that arthritic rats would exhibit a different response.
THC and anandamide appear to release an as yet unknown endogenous opioid, because naloxone significantly blocked their effects.
This study indicates that anandamide and THC may act at different receptor sites to modulate endogenous opioid levels in mechanical nociception.”