DID test, no choice is offered—the animals, for a 2 or 4 h period, have only access to ethanol. While they do not have to drink in order to maintain a normal physiological state [i.e., they are not fluid-deprived (Toth and Gardiner 2000)], the face validity of the model would be improved if a choice were offered. However, in the F2 cross of C57BL/6J and DBA/2J, ethanol intake was reduced when water was offered as an alternative drinking solution (Phillips et al. 2010). Todd Thiele's group has performed studies in C57BL/6J mice where periods of food deprivation were shown not to affect intake or BEC in DID drinking (Lyons et al. 2008). Peripheral administration of the anorectic agent leptin had no effect on DID intake or BECs, though separate tests showed its effectiveness in reducing food intake. Ghrelin similarly enhanced eating, but showed only a modest tendency to increase alcohol intake/BEC. The alcohol drinking experiments were conducted with food removed. These studies suggest that the DID phenotype is not primarily related to feeding behavior, or at least to calorie-seeking (Lyons et al. 2008). In another application of the method, Boehm et al. have used the DID procedure to offer high
