Mediation of separation distress by α₂-adrenergic mechanisms in a non-human primate

This study provides the first behavioral evidence in support of an α-adrenergic mechanism underlying imipramine's amelioration of separation distress. The rate of separation-induced vocalization by adult squirrel monkeys was decreased by imipramine and the α₂-adrenergic agonist clonidine, and increased by the α₂-adrenergic antagonist yohimbine. Yohimbine, but not the α₁-antagonist prazosin, reversed the clonidine effect suggesting that drugs acting directly on α₂-receptors may have a role in management of separation anxiety.