Reports of KOR blockade on home-cage ethanol consumption are more consistent, with most studies demonstrating reduced intake (Table 2). However, numerous reports observed that antagonism of KORs reduced ethanol intake in stressed or ethanol-dependent subjects, but not in non-stressed or non-dependent subjects (Karkhanis et al., 2016a; Sperling et al., 2010; Anderson et al., 2016; Rose et al., 2016). These findings are described in greater detail later in this review. Although minimal work has examined sex differences, a couple of reports have suggested that effects of KOR antagonism on home-cage drinking may differ between male and female subjects. Specifically, nor-BNI was reported to increase ethanol consumption in male rats while decreasing ethanol intake in female rats (Morales et al., 2014). Conversely, a recent study reported that nor-BNI administration reduced ethanol consumption in male mice, but had no effect in female mice (Zhou et al., 2017).
