Intrathecal BK administration-induced mechanical hypersensitivity was enhanced by OLDA co-administration. Low dose of OLDA (0.42 µg) and BK (21.2 µg, i.t., n = 6) co-administration protracted BK-induced mechanical allodynia using the von Frey filaments, with bending forces of 35 mN and 59 mN (A), and hyperalgesia using filaments with bending forces of 80 mN, 140 mN, 290 mN, and 370 mN (B). Data represent the mean ± S.E.M. of 6 (BK + OLDA) and 6 (vehicle) independent experiments. Statistical analysis: Mann-Whitney rank test; * p < 0.05, ** p < 0.01, *** p < 0.001 left hindpaw, BK + OLDA versus vehicle treatment; #
p < 0.05, ##
p < 0.01, ###
p < 0.001 right hindpaw, BK + OLDA versus vehicle treatment. The time of the i.t. administration is marked by arrows.