Influence of fibroblast-like synovial (FLS) cells on the expression of transient receptor potential V1 (TRPV1) receptor-like immunoreactivity in dorsal root ganglion (DRG) neurones. (a) Labelled DRG neurones (see arrows) expressing TRPV1 receptor-like immunoreactivity after co-culture with FLS cells isolated from acutely inflamed knee joints. (b) Same cells as in (a) double-labelled with an anti-neurone-specific enolase antibody. Scale bar, 10 μm. (c) Influence of FLS cells isolated from normal, acutely and chronically inflamed knee joints on the expression of TRPV1 receptor-like immunoreactivity in co-cultured DRG neurones. #Significant difference to DRG mono-cultures. $Significant difference to co-culture with FLS cells from normal knee joints. AIA, antigen-induced arthritis.