TNFR1 mRNA is increased following inflammation in the dorsal root ganglion (DRG). (a) Real-time RT-PCR showed a threefold increase in mRNA of tumour necrosis receptor type 1 (TNFR1) (expressed as the ratio of TNFR1 mRNA to 18S mRNA) in the DRG following the induction of inflammation by complete Freund's adjuvant (CFA) (n = 4). The increase was bilateral, being observed on both the ipsilateral (black bars) and the contralateral (white bars) DRGs. (b) In situ mRNA hybridisation showed no TNFR1 detection in the naive DRG. (c) In situ hybridisation for TNFR1 in the ipsilateral DRG 7 days after inflammation showed receptor expression in neuronal cells. *P < 0.05, **P < 0.01.