Fig. 1. Acute nociceptive responses in B1/B2KO mice. (A ) Mechanical thresholds measured by von Frey test in B1/B2 knockout (B1/B2KO) mice and wild type (WT) mice (n = 21 per group). (B ) Thermal thresholds measured with Hargreaves test in B1/B2KO and WT mice (n = 16 per group). (C ) Bradykinin-induced nociception in B1/B2KO and WT mice (n = 8 per group). The number of flinches was measured for 25 min after intraplantar injection of BK (30 nmol/paw). (D ) Acetic acid–induced writhing in B1/B2KO and WT mice (n = 8 per group). The number of writhes was measured for 30 min after intraperitoneal injection of acetic acid (0.6%). Student's unpaired t  tests (A, B, D ) and two-way repeated measures ANOVA followed by Bonferroni test (C ) were performed. *P < 0.05, **P < 0.01, ***P < 0.005 vs . WT. Blue bars : WT mice; red bars : B1/B2KO mice.