COMMD3 and opiate dependence: In addition, BUP has also been shown to block the action of k agonists [56] and a functional k antagonism has been proposed on the basis of the results derived by animal models to function therapeutically as an antidepressant compound in humans [24] (this is the hypothesized mechanism underlying the efficacy of BUP/naltrexone combination therapy for opioid dependence [50]).