Circadian drinking rhythms and blood alcohol levels in two rat lines developed for their alcohol consumption

The circadian drinking behavior of the AA (Alko Alcohol) and ANA (Alko Non-Alcohol) rat lines developed for high and low voluntary alcohol consumption was studied by using a microcomputer lick-counting system. The blood alcohol concentrations of AA rats were measured during the drinking peaks. The results showed that AA rats voluntarily drink intoxicating amounts of alcohol. The highest blood alcohol levels were about 25 mmol/l. Differences in circadian drinking rhythms between AA and ANA lines were also found. AA rats had a trimodal drinking pattern for alcohol intake during the dark period but ANA rats drank alcohol rather evenly throughout the period.