Double-immunofluorescence labelling illustrated the expression of TRPC5 in the intimal and subintimal lining of the mouse synovium (figure 1B), with co-localisation with CD55 observed mostly in the intimal lining, as previously described.10 The functional contribution of TRPC5 in vivo was investigated by assessing mobility and movement-related pain over a period of 14 days, following CFA-induced arthritis. The gene discussed is TRPC5; the disease is arthritic joint disease.