Chunk #22 — Effects of DYN/KOR Activity on Ethanol-Conditioned Behavior and Consumption — Operant Ethanol Self-Administration and Relapse-Like Behavior
Finally, cue-induced reinstatement of ethanol responding has been shown to be reduced by the KOR antagonists nor-BNI and JDTic (Berger et al., 2013; Schank et al., 2012a). Interestingly, although KOR antagonists have been shown to attenuate stress-induced reinstatement of responding for drugs of abuse such as cocaine (Graziane et al., 2013; Polter et al., 2014), this effect has not been observed with ethanol (see Schank et al., 2012a). Providing further evidence for a distinction between cue- and stress-induced reinstatement, naltrexone, a nonspecific opioid antagonist, was reported to block cue but not footshock stress-induced reinstatement of operant responding for ethanol (Le et al., 1999; Liu and Weiss, 2002). KOR antagonists, however, were shown to block reinstatement of ethanol seeking behavior induced by the pharmacological stressor yohimbine (Funk et al., 2014). Of note, two studies reported that systemic administration of the KOR agonist U50,488 reinstated responding for ethanol after extinction (Funk et al., 2014; Harshberger et al., 2016). These findings suggest that KOR activation may underlie, at least in part, the ability of stress to provoke relapse-like responding for ethanol. Further discussion of interactions of stress and ethanol occur later in this review.
