Fig. 4.
Taste-salient brief-access tests of quinine and sucrose responsiveness of mice bearing long-term constitutive loss of RGS21 expression. (A) Schematic representation of timing of brief-access tests for quinine (“aversive stimulus”; Table (i)) and for sucrose (“preferred stimulus”; Table (ii)) performed with 8-week-old (postnatal [P] day 56) constitutive Rgs21 knockout mice (Rgs21Δ5/Δ5) and wild-type Rgs21+/+ littermate controls. (B) Lick ratios (between indicated quinine sulfate concentration vs unadulterated water) were analyzed by two-way ANOVA with Sidak posthoc testing for differences by genotype (n = 6 for Rgs21+/+ and n = 7 for Rgs21Δ5/Δ5; ns, not significant [P >> 0.05]; **, P < 0.01; ****, P < 0.0001). (C) Data from brief-access to sucrose are reported as the ratio of concentration-specific-licks-to-total-licks to account for motivational differences between mice tested (i.e., the horizontal dashed line represents the expected value of the ratio [0.2] from completely random licking of all 5 concentrations). (D) Two-bottle choice preferences of Rgs21Δ5/Δ5 (n = 7) and wild-type mice (n = 7) for ascending concentration series of sucrose, as previously conducted for quinine sulfate and NaCl (Fig. 3; (Schroer et al. 2018)). Each test was assessed with a two-way ANOVA. Differences between the groups at specific concentrations of taste solution were determined using Sidak posthoc test to correct for multiple comparisons (* P < 0.05; ** P < 0.01; **** P < 0.0001).