(A) Changes of B
R mRNA levels in the lumbar spinal cord of capsaicin-treated rats (0-50 mg/kg, s.c.). Data represent the means ± S.E.M. of 4 to 7 rats per group (a single dose of capsaicin per group, 24 h earlier). Comparison with the 0 mg/kg group is indicated by * P < 0.05; ** P < 0.01. (B) Time-course effect (0 - 48 h) of 15 mg/kg (•) and 50 mg/kg (□) capsaicin on lumbar spinal cord B1R mRNA expression levels. Data represent the means ± S.E.M. of 4 rats per group. Comparison with the 0 h group (*) is indicated by ** P < 0.01; *** P < 0.001. Shown are the responses in rats housed under constant light (A) or a 12 h-12 h light-dark cycle (B).