Tomato juice, chocolate drink, and other fluids suppress volitional drinking of alcohol in the female syrian golden hamster

Abstract

Although the hamster generally prefers alcohol at a level similar to that of the rat or mouse selectively bred to consume alcohol, the drinking hamster demonstrates neither physical dependence on alcohol nor elevated blood levels of alcohol, which are two typical criteria characterizing an animal model of alcoholism. The present investigation was designed to determine whether a third criterion of an animal model (i.e., consumption of high levels of alcohol in the presence of a palatable fluid, fulfilled by the P rat) would be met by the female Syrian golden hamster ( Mesocricetus auratus). A standard 3-bottle preference test was undertaken in 6 female hamsters over an 11 day period, in which water was presented in one tube and, in a second tube, a v/v solution of alcohol which was increased in concentration from 3% to 50% on each day as follows: 3%, 5%, 7%, 9%, 12%, 15%, 20%, 25%, 30%, 40%, and 50%. Then each hamster was offered its individually determined, maximally preferred concentration of alcohol for 4–8 days, which was 20%, 25%, or 30% alcohol. The mean absolute intake of alcohol during this period was 17.9 ± 1.1 g/kg per day, whereas the mean proportion of alcohol to total fluid was 0.68 ± 0.05. Then over a 4-day interval, a solution of tomato juice, peach juice, mango juice, dextrose and a chocolate beverage (Ensure Plus), all made isocaloric to the alcohol solutions with dextrose, was placed in the third tube simultaneously with water and the individually preferred concentration of alcohol. The results showed that each of the palatable fluids reduced significantly the intake of alcohol of the hamsters below that of the preferred concentration selected during each test sequence. The chocolate drink reduced the intake of alcohol most potently, with the mean intake falling by more than 50% to 8.0 ± 0.4 g/kg per day. Interestingly, this suppression of alcohol intake did not differ significantly from that reported in hamsters administered pharmacological agents including kudzu derivatives. Since a palatable and/or nutritious fluid acts to attenuate drinking, the hamster may not represent a valid animal model for exploring the therapeutic utility of drugs for alcohol abuse or alcoholism.