OPRK1 and alcohol dependence: Naltrexone is one pharmacotherapy used in the management of alcohol dependence that works by modulating opioid control of dopaminergic cell firing in the ventral tegmental area, thus preventing an increase in dopaminergic activity.17 The endogenous opioid system has been implicated in emotion regulation.18 There is some evidence of naltrexone dampening responses to negative emotional stimuli in healthy adults,19 although this likely reflects stress-reducing effects of the potent kappa-opioid receptor (KOR) antagonist actions of naltrexone.