Studies in mice have been able to make use of transgenic strains that lack functional copies of the CB1 gene. Vinod et al (2008b) found that treatment of either C57BL/6 or DBA/2 mice with SR reduced ethanol preference to levels comparable to mice with these genetic backgrounds but lacking a functional copy of the CNR1 gene. Reduced ethanol consumption and preference in CB1 KO mice has been replicated in other labs (Naassila et al., 2004) including in ethanol dependent mice (Lallemand and De Witte, 2005), and Racz et al (2003) found that CB1 KO mice do not exhibit the increase in ethanol consumption observed in wt controls following acute stress. Interestingly, this study failed to find the reduced ethanol preference in CB1 KO mice reported elsewhere, and in fact, it reported that these mice had a higher preference for ethanol during the first few days of access (Racz et al., 2003). However, an important methodological difference separating this study from the others is that the ethanol was available ad libitum for several weeks, and while the initial pattern of drinking
