Suppression of acquisition of alcohol-drinking behavior by the concurrent availability of saccharin in Sardinian alcohol-preferring (sP) rats

In the current study, we investigated the effect of the concurrent presentation of saccharin on the acquisition of alcohol-drinking behavior in selectively bred Sardinian alcohol-preferring (sP) rats. Alcohol-naive rats were given access to saccharin [0%, 0.01%, 0.1%, 1%, or 3% (weight/volume) in water], alcohol [10% (volume/volume) in water], and water under the home cage, three-bottle, free-choice regimen, with unlimited access for 24 h/day for 10 consecutive days. Intake of saccharin solution resulted as an inverted-U function of saccharin concentration, reaching polydipsic-like values at the 0.1% concentration. In contrast, alcohol intake was a U function of saccharin concentration, being virtually suppressed in the groups of rats exposed to the highly accepted 0.1% and 1% concentrations of saccharin. These results indicate that (1) the concurrent presentation of highly palatable solutions of saccharin suppresses acquisition of alcohol-drinking behavior in sP rats and (2) the suppressive effect of saccharin solutions on the acquisition of alcohol-drinking behavior in sP rats was positively related to their degree of acceptability. We hypothesize that an immediate and continuous access to the highly palatable saccharin solution may have distracted the rat, preventing it from consuming the amounts of alcohol solution needed to disclose and experience the psychopharmacologic effects of alcohol on which alcohol-drinking behavior in sP rats is based.