To drink or not to drink: tests of anxiety and immobility in alcohol-preferring and alcohol-nonpreferring rat strains.

Previous reports have provided mixed results about emotional states in rats that voluntarily drink substantial amounts of alcohol. The purpose of the present study was to compare several strains of alcohol-preferring rats (P, AA, FH) with several strains of alcohol-nonpreferring rats (NP, ANA, FRL), and the Maudsley strains on tests reflecting anxiety and immobility. At about 70 days of age the rats were placed in the elevated plus maze for a 5-min test; a forced swim test of 10 min was given 4 days later and this test was followed 4 days later by a modified forced swim test (the capsule), in which there were four false escape alleys. The FRL rats spent more time in the open arms of the elevated plus maze than any other strain, but there was no consistent relationship between elevated plus maze scores and alcohol intake. The alcohol-preferring P rats were the most active in the standard forced swim test and the alcohol-nonpreferring Maudsley Reactive rats were the least active, but there was no consistent relationship between immobility and alcohol intake overall. All rats were much more active in the capsule and there were no significant strain differences. However, the alcohol-preferring P and FH rats attempted to escape more than the other strains, resulting in an overall significant correlation between escape attempts and alcohol intake. These findings do not provide any support for the hypothesis that alcohol-preferring rats are drinking alcohol to reduce high anxiety states.