Sucrose versus Ethanol Appetite in Inbred Strains of Mice

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Abstract
Marked differences have been demonstrated among inbred strains of mice in preference for a 10% solution of ethanol offered as an alternative to water. Calorie appetite has been suggested as a basis for these differences, and sucrose feeding has been used to reduce alcohol intake of rats that voluntarily ingest alcohol in preference to water. The present study explores the relative strength of sucrose preference versus alcohol preference or aversion in 9 strains of mice, explores ways of inducing voluntary consumption of alcohol by strains that normally avoid it, and further examines the nature of alcohol appetite in mice. In one study, 5 adult C57BL/Crgl mice were offered a choice among a 10% ethanol solution, a 15% sucrose solution, and water. In a second study, 5 mice each of the A/Crgl/2, A/Crgl/3, AKR/Crgl, BALB/cCrgl, C3H/Crgl, C3H/Crgl/2, C57BL/Crgl, DBA/ 2Crgl, and RIII/Crgl strains were offered a choice between water and one of five different 10% alcohol solutions containing from 0 to 16 g of sucrose/100 ml of solution, in a systematic sequence over a 30-day period. These animals were then offered a choice between 15% sucrose solution and water for an additional 4-day period. All strains showed greater preference for sucrose solution than for either water or alcohol solution. All strains showed greater preference for sweetened alcohol solutions than for nonsweetened alcohol solutions, and increasing preference for increasingly sweetened solutions. The results are interpreted as indicating that volume of liquid consumed is a probable mechanism by which alcohol intake is reduced when a sucrose solution is simultaneously available. They are also interpreted as indicating the presence of a metabolic tolerance factor that limits alcohol intake, independent of caloric appetite; and data are cited suggesting that the strains may consume sweetened alcohol solutions in quantities that approach their physiological ability to metabolize the alcohol. Further evidence was obtained concerning strain differences in aversion to alcohol among the normally low-preference strains, suggesting that the DBA/2 and the A/3 strains have the greatest aversion to alcohol while the BALB/c and A/2 have somewhat less aversion. The C57BL, as in previous studies, has the highest alcohol preference; and the C3H/2, C3H, and RIII are next highest in preference for alcohol, on the average, whether sweetened or not. The AKR strain shows marked individual differences in consumption patterns, suggesting that this strain may be unusually susceptible to the influence of previous ingestion of alcohol on subsequent preference. With the possible exception of the AKR strain, preference for or av ersion to alcohol of naive mice of the strains tested is shown to be weak as compared to their preference for sucrose. Previous findings of a marked genetic role in alcohol preference are confirmed and the practicality of using sweetened alcohol to induce some voluntary ingestion in normally low-preference strains is demonstrated.