“The participation of endocannabinoids in central and peripheral antinociception induced by several compounds has been shown by our group.
In this study, we investigated the effect of endocannabinoids on the central antinociception induced by ketamine.
It was concluded that central antinociception induced by ketamine involves the activation of CB1 cannabinoidreceptors.
Mobilization of cannabinoids might be required for the activation of those receptors, since inhibitors of the endogenous cannabinoids potentiate the effect of Ketamine.”
https://www.ncbi.nlm.nih.gov/pubmed/30716423
https://www.sciencedirect.com/science/article/abs/pii/S0304394019300771?via%3Dihub