BNP inhibits inflammatory pain. A) BNP (0.04 nmol, i.t.) did not alter the baseline of thermal sensation as tested in a 50°C tail-immersion assay. n = 9, p > 0.05, one-way ANOVA. B) BNP significantly reduced the licking and flinching time induced by capsaicin (2 μg, i.pl.). n = 10. *p < 0.05 versus saline, unpaired t test. C) BNP (0.1 nmol, i.t.) did not change the first phase (0–10 min), but significantly reduced the second phase (10–60 min) of formalin pain. n = 6–7. *p < 0.05 versus saline, unpaired t test. D) Pre-injection of BNP (0.04 nmol, i.t.) 10 min before morphine injection (5 mg/kg, i.p.) significantly blocked morphine analgesic effect as tested by tail-immersion assay 60 min after morphine injection. n = 6. *p < 0.05 versus pre-saline + morphine, unpaired t test.