TRPA1 and rheumatoid arthritis: It is demonstrated that not cannabinoid receptors but transient receptor potential channels (TRPs) vanilloid type 1 (TRPV1) and ankyrin (TRPA1) mediate the anti-inflammatory effects of WIN in physiological concentrations on rheumatoid arthritis synovial fibroblasts (RASFs) and osteoarthritis synovial fibroblasts (OASFs).