A few studies have examined the effects of KOR antagonists on ethanol-induced CPP or CTA. One study in female mice reported similar ethanol-induced CPP in subjects pretreated with the long-acting KOR antagonist nor-binaltorphimine (nor-BNI) relative to saline, but when subjects were retested in the presence of ethanol (referred to as state-dependent CPP), a greater CPP effect was observed in nor-BNI treated mice (Nguyen et al., 2012). Another study reported no effects of nor-BNI treatment on ethanol CPP in non-stressed male mice (Sperling et al., 2010). Two studies conducted in rats have shown that nor-BNI does not alter ethanol-induced CTA whether administered 24 hr before conditioning (Roma et al., 2008) or 24 hr before testing (Anderson et al., 2013). Collectively, these findings suggest that KOR blockade does not influence ethanol-induced CTA or CPP (at least in standard paradigms that assess these effects in an ethanol-free state). Studies focused on stressed-induced ethanol CPP are described later in this review.
