Fig. 2.

Effects of antagonism of the alpha-2 adrenoreceptor on the antinociceptive effect of i.t. nefopam. Yohimbine, an antagonist of the alpha-2 receptor, but not the alpha-1 receptor, reduces partially, but significantly, the antinociceptive effect of i.t. nefopam during phase 1. During phase 2, the flinching responses of nefopam-treated animals are not different from those of the yohimbine plus nefopam-treated group. ^*Indicates P < 0.05, ^†P < 0.01.