Intake of ethanol, sodium chloride, sucrose, citric acid, and quinine hydrochloride solutions by mice: a genetic analysis

Abstract

Mice of the 129/J (129) and C57BL/6ByJ (B6) strains and their reciprocal F1 and F2 hybrids were offered solutions of ethanol, sucrose, citric acid, quinine hydrochloride, and NaCl in two-bottle choice tests. Consistent with earlier work, the B6 mice drank more ethanol, sucrose, citric acid, and quinine hydrochloride solution and less NaCl solution than did 129 mice. Analyses of each generation's means and distributions showed that intakes of ethanol, quinine, sucrose, and NaCl were influenced by a few genes. The mode of inheritance was additive in the case of ethanol and quinine, for sucrose the genotype of the 129 strain was recessive, and for NaCl it was dominant. Citric acid intake appeared to be influenced by many genes with small effects, with the 129 genotype dominant. Correlations of sucrose consumption with ethanol and citric acid consumption were found among mice of the F2 generation, and the genetically determined component of these correlations was stronger than the component related to environmental factors. The genetically determined correlation between sucrose and ethanol intakes is consistent with the hypothesis that the higher ethanol intake by B6 mice depends, in part, on higher hedonic attractiveness of its sweet taste component.

Fig. 1

Solution intake of 129 and B6 mice. Vertical bars represent SE.

Fig. 2

Solution intake of reciprocal F₁ and F₂ hybrids: 129 × B6 cross originates from female 129 and male B6 mice; B6 × 129 cross originates from female B6 and male 129 mice. Vertical bars represent SE.

Fig. 3

Solution intake of male 129, B6, F₁, and F₂ mice. (●) Parental strains and midparental value; (▴) F₁; (∎) F₂. Vertical bars represent SE.

Fig. 4

Frequency distribution of solution intake in male 129, B6, F₁, and F₂ mice. Bin sizes are 2 ml/30 g BW for sucrose intake and 0.5 ml/30 g BW for other solutions.

Fig. 5

Codistribution between individual values of citric acid and ethanol intake with sucrose intake in F₂.