Changes in IL-1β and TNF-α mRNA levels in lumbar spinal cord of capsaicin-treated rats (0-50 mg/kg, s.c. 24 h earlier). Also shown is the effect of the TRPV1 antagonist capsazepine (10 mg/kg, i.p.) administered 1 h prior to capsaicin. Data represent the means ± S.E.M. of 5-7 rats in each group. Comparison with vehicle (0 mg/kg) (*) is indicated by * P < 0.05.