SARDINIAN ALCOHOL-PREFERRING RATS PREFER CHOCOLATE AND SUCROSE OVER ETHANOL

The present study was aimed at determining whether the concurrent avai lability of highly palatable fluids (i.e., a chocolate-flavored drink and a sucrose solution) would alter voluntary ethanol drinking in sele ctively bred, alcohol-preferring sP and -nonpreferring sNP rats. Ethan ol intake occurred under the three-bottle, free choice regimen between 10% (v/v) ethanol solution, tap water, and the palatable fluids for 2 4 h per day. When rats were given ethanol and water, but no alternativ e fluids, mean ethanol intake in sP rats ranged between 6 and 7 g/kg p er day and mean preference ratio was steadily higher than 80%, whereas mean ethanol intake and preference ratio in sNP rats were constantly lower than 0.3 g/kg and 5%, respectively. In the presence of either th e chocolate-flavored drink or sucrose solution, both prepared as isoca loric to the ethanol solution, absolute ethanol intake in sP rats decl ined by 60-70%; similarly the preference ratio was reduced by 80-90%. Ethanol intake in sNP rats was unaffected by the simultaneous presenta tion of either palatable fluids. The results of the present study clos ely replicate those previously reported in genetically selected, ethan ol-preferring HAD rats; however, they differ from those of ethanol-pre ferring P rats, which were reported to maintain high levels of ethanol intake and preference in the presence of highly palatable fluids. The se results are discussed in terms of a) an alternative reinforcement p artially substituting for the reinforcing properties of ethanol in sP rats, resulting in a less urgent need of ethanol, and b) genetic anima l models of alcoholism diverging in some neurochemical and behavioral traits (e.g., response to the presentation of palatable fluids), which might parallel the different types of alcoholism observed in humans. (C) 1997 Elsevier Science Inc.