preferring rat strain, Adams et al (2010) reported that low doses of SR that did not alter ethanol self-administration on their own could be combined with sub-threshold doses of either an adenosine A2A or mGluR5 antagonist to reduce ethanol responding. Lastly, one study examining the interaction between alcohol dependence and the effect of SR treatment on operant responding for ethanol found that SR reduced ethanol self-administration in dependent rats but did not affect the response rate of control treated rats (Rodríguez de Fonseca et al., 1999).