A growing body of literature has emerged implicating a significant role for the DYN/KOR system in the motivational effects of ethanol. These studies have employed various models and experimental approaches. As highlighted in this review, results from this body of work are often inconsistent. This is likely due to numerous factors including differences in experimental parameters as well as limited analysis of the topic. Nevertheless, studies have consistently supported the contention that the DYN/KOR system plays a significant role in contributing to dependence- and stress-induced increases in ethanol consumption. Figure 1 provides a conceptual overview of adaptations in the DYN/KOR system that may influence the rewarding effects of ethanol. Activation of this endogenous opioid peptide system has been shown to produce a negative hedonic state. Consequently, under conditions in which the DYN/KOR system is engaged (following stress or chronic ethanol exposure/withdrawal experience), the relative rewarding effects of ethanol may be enhanced, potentially contributing to elevated ethanol consumption. Under these circumstances, administration of a KOR antagonist may restore normal (basal) hedonic balance, thereby moderating ethanol reward and motivation to drink (Figure
