Table 1.
List of bitter compounds and concentrations (mM) used in this study.
Fig 1.
Typical experimental schedules for the measurement of rejection (RjT) and apparent recognition (aRcT) thresholds for bitter compounds.
RjTNE and aRcTNE are defined as values measured without 3 weeks of a bitter exposure period (NE group), whereas RjTE and aRcTE as values measured after the continuous bitter exposure period (E group).
Fig 2.
Two-bottle preference ratios for concentration series of L-tryptophan (n = 8) and L-isoleucine (n = 8) measured before (closed circles) and after (open circles) poisoning with LiCl.
# and * indicate the lowest concentrations at which preference ratios fell significantly (p < 0.05) below indifference (0.5) before and after CTA, respectively. Solid and dashed lines represent curves fit to the average ratios before and after CTA, respectively. Gray lines represent the indifference level (0.5).
Table 2.
Summary of ANOVA results for preference scores.
Table 3.
Rejection and recognition thresholds for various bitter compounds.
Fig 3.
Two-bottle preference ratios for concentration series of denatonium benzoate (DB, n = 8), quinine hydrochloride (QHCl, n = 7), caffeine (CAF, n = 8), salicin (SAL, n = 8), and epigallocatechin gallate (EGCG, n = 8) measured before (closed circles) and after (open circles) poisoning with LiCl.
# and * indicate the lowest concentrations at which preference ratios fell significantly (p < 0.05) below indifference (0.5) before and after CTA, respectively. Solid and dashed lines represent curves fit to the average ratios before and after CTA, respectively. Gray lines represent the indifference level (0.5).
Fig 4.
The average volume of daily solution intake per mouse during the prolonged bitter exposure period.
The shadow indicates the period when water was replaced with a bitter solution.
Fig 5.
Two-bottle preference ratios for concentration series of DB (n = 8), QHCl (n = 7), CAF (n = 8), SAL (n = 8), and EGCG (n = 8) measured after a 3-week period of exposure to the same bitter compound (open circles) superimposed on those measured without the exposure period (closed circles).
# and * indicate the lowest concentrations at which preference ratios fell significantly (p < 0.05) below indifference (0.5) before and after the long bitter exposure, respectively. Solid and dashed lines represent curves fit to the average ratios for the NE and E groups, respectively. Gray lines represent the indifference level (0.5).
Table 4.
Summary of ANOVA results for preference scores.
Fig 6.
LiCl-conditioned avoidance of DB (n = 6), QHCl (n = 7), CAF (n = 7), SAL (n = 8), and EGCG (n = 6) in two-bottle choice tests after a 3-week period of exposure to the same bitter compound (open circles) superimposed on those measured without the exposure period (closed circles).
# and * indicate the lowest concentrations at which preference ratios fell significantly (p < 0.05) below indifference (0.5) before and after the long bitter exposure, respectively. Solid and dashed lines represent curves fit to the average ratios for the NE and E groups, respectively. Gray lines represent the indifference level (0.5).
Table 5.
Summary of ANOVA results for preference scores.