“The … of yohimbine (a nonselective α₂-adrenoceptor antagonist, 1 mg/kg), BRL-44408 (an α(2A)-adrenoceptor antagonist, 1 mg/kg) or MK-912 (an …-adrenoceptor antagonist, 300 μg/kg) but not imiloxan (an α(2B)-adrenoceptor antagonist, 1 mg/kg) inhibited the antinociceptive effect of imipramine (20 …/kg).”