Two-bottle preference experiments with water and 200mM sucrose before and after treatment with naloxone

Two-bottle preference experiments with water and 200mM sucrose before and after treatment with naloxone. In the first set of experiments in Figure 7A, three mice had continual access to water and sugar solution. The animals were trained for three days before receiving naloxone treatment. For each day, the total amounts of each liquid consumed were used to calculate the preference score [sucrose (mL)/total fluid (mL)] such that the higher the score indicates the greater the sweet preference with 0.5 representing no preference. In the second set of experiments in Figure 7B, four mice were placed on a 22.5 hour water deprivation schedule where they had access to bottles of water and sugar solution the remaining 1.5 hours per day.