Effects of time of day and constant light on the behavioral responses and ethanol metabolism to acute alcohol administration in male Black Swiss mice

Alcohol modulates the circadian clock at both the behavioral and molecular levels. Additionally, alcohol consumption is well-known to affect anxiety in both animal and human studies. Disruptions to the circadian rhythm can also lead to alterations in anxiety. This study investigated whether there are day/night variation and effects of constant room-level light (LL) on anxiety-like behaviors and ethanol metabolism after moderate alcohol treatment. Mice were entrained to a 12:12 Light:Dark (LD) cycle and split into ethanol and control groups. One-half of each group was tested for anxiety-like behaviors and ethanol metabolism during the day, while the other half was tested during the night. A new group of mice were either exposed to LL or a 12:12 LD cycle and their ethanol-induced anxiety behaviors and ethanol metabolism were observed. While ethanol injections reduced anxiety and increased exploration in the open field and light-dark box, there were no differences in the response to ethanol between day testing and night testing. LL produced modulations to ethanol-related anxiety and exploration, but had no effect on ethanol metabolism. These results indicate that circadian dysregulation can alter the behavioral response to acute alcohol intake, independent of ethanol metabolism and regardless of the time of day.