2.3. Forced swim test

The FST was used as a physical stressor and was administered between 1,500 and 1,700 hr (during their dark phase) each day for three consecutive days. During the FST, mice were maintained on the two‐bottle choice paradigm, that is, water and 11% EtOH. The only time that ethanol was not available to the experimental animals was during the FST. Mice were placed into a 19‐cm diameter Plexiglas tank filled to 24 cm with 24°C water for 10 min, as previously described by H. K. Caldwell, Dike, Stevenson, Storck, and Young (2010). Animals were videotaped and the test timed using a stopwatch. The duration of time struggling (swimming) versus. immobility was scored and calculated using Observer® (Noldus Technologies, Leesburg, VA), a behavioral coding software program. During scoring, minutes 2 through 6 were scored for each animal (total of 4 min), of which a 5‐s sampling method was utilized which categorized a mouse's behavior as swim or float. A swim behavior was defined as all four paws or the back two paws moving to propel mouse. A float behavior was defined as no paws moving or back two paws moving.