“…We have found that ethanol consumption among animals tested using this paradigm is both influenced by genetic variants (lopioid) that increase alcohol-induced stimulation and is sensitive to l-opioid receptor blockade (S. Chen, unpublished data), providing evidence that reward pathways are involved. However, as research performed in rodents has shown, oral self-administration of ethanol is driven by numerous factors in addition to reinforcement (Samson et al, 1998(Samson et al, , 2000(Samson et al, , 2004. Our data appear to support this as well, in that the lack of similar associations in the other testing groups, while possibly related to the smaller sample sizes, argues against a strict relationship between reinforcement ⁄ reward and voluntary ethanol consumption.…”