- CB1 and CB2 protein and RNA were present in synovia of OA and RA pts- Cannabinoid receptor stimulation time-dependently activated MAPK/ERK1/2, which is blocked by SR141716A (CB1 antagonist)- AEA and 2-AG found in synovia of OA and RA pts but not healthy volunteers- Fatty acid amide hydrolase active in synovia of OA and RA pts. Here, CNR2 is linked to rheumatoid arthritis.