Antinociceptive effect of i.c.v. injections of Thr6-BK or BK. (a) Time course of the increase in latencies in the tail flick test induced by i.c.v. injection of Thr6-BK (8 nmol) and BK (4, 8 and 16 nmol). (b) AUC of the groups shown in (a). (c) Time course of the increase in latencies in the hot-plate test induced by i.c.v. injection of Thr6-BK (8 nmol) and BK (4, 8 and 16 nmol). (d) AUC of the groups shown in C. *Significantly different from control (*P<0.05 **P<0.001); #significantly different from 8 nmol Thr6-BK, and + significantly different from 16 nmol BK. AUC, area under the curve of antinociception; IA, index of antinociception; Thr6-BK, threonine6-bradykinin.