TRPV1 agonist i.t. treatment enhanced BK-induced thermal hyperalgesia in a time-dependent manner. A detailed comparison of the effects of the drugs, 1 h and 2 h after the i.t. administration. (A) Co-administration of BK (21.2 μg) and OLDA (0.42 µg) decreased the PWL 1 h after i.t. treatment to a similar level as BK alone. (B) Co-administration of BK and OLDA, enhanced the thermal hyperalgesia 2 h after i.t. treatment, as compared to BK alone. Data represent the mean ± S.E.M. with a scatterplot of the individual data points of 4–7 independent experiments. Statistical analysis: One-way ANOVA followed by Tukey’s test; *** p < 0.001, **** p < 0.0001, versus vehicle i.t. treatment; +
p < 0.05, ++
p < 0.01, ++++
p < 0.0001, versus BK + OLDA i.t. treatment.