Mediation of separation distress by alpha 2-adrenergic mechanisms in a non-human primate.

This study provides the first behavioral evidence in support of an alpha-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 alpha 2-adrenergic agonist clonidine, and increased by the alpha 2-adrenergic antagonist yohimbine. Yohimbine, but not the alpha 1-antagonist prazosin, reversed the clonidine effect suggesting that drugs acting directly on alpha 2-receptors may have a role in management of separation anxiety.