We have discussed elsewhere many other procedures that have been effectively used to increase drinking in rodents (12) (see also Supplement 1). These have their uses, and some can lead to very high BECs, but nearly all require a significantly greater degree of training over a longer period. Alternatively, they may require either food or water deprivation (or both). The animals in the DID procedure are never food or fluid deprived. A nonpreferring mouse must withhold drinking for the 4-hour period of the test, but this is easily tolerated without adverse physiological consequences (24). We do not know why some mice elect to drink a great deal during the DID procedure and others do not. Taste is a complex phenotype, and genetic influences are an important contributor to taste preferences for various tastants (e.g., salt, sweet) (25). An extensive literature supports a role for taste in two-bottle ethanol preference drinking (for reviews, see refs. 26,27). Thus, it will be important to explore taste sensitivity and preferences in the HDID-1 mice. We would predict that a genotype that voluntarily drinks 20%
