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

The present study 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% w/v, in water), alcohol (10% v/v, in water) and water under the homecage, 3-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 concentration of 0.1%. On the contrary, alcohol intake was a U function of saccharin concentration, being virtually suppressed in the rat groups exposed to the highly accepted saccharin concentrations of 0.1 and 1%. These results indicate that (a) the concurrent presentation of highly palatable solutions of saccharin suppresses acquisition of alcohol drinking behavior in sP rats, and (b) the suppressive effect of saccharin solutions on the acquisition of alcohol drinking behavior in sP rats was positively related to their degree of acceptability. It has been hypothesized 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 psychopharmacological effects of alcohol at the basis of sustained alcohol drinking behavior in sP rats.