Figure 2.

Taste sensitivities to various stimulants in heterozygous DGsα-null mutants. Each column represents the mean ± SEM of 10 experiments. A, The amount of intake of 20 mm trehalose, 5 mm sucrose, 20 mm fructose, and 20 mm glucose in cn bw/+ flies (filled columns) and DGsα^R19/+ (open columns). The amount of intake in each sugar solution in DGsα^R19/+ flies was significantly lower than that in cn bw/+ flies (asterisks, p < 0.05). B, The preference indexes for the control solution over bitter solutions in cn bw/+ flies (filled columns) and DGsα^R19/+ (open columns). The control solution used for quinine and denatonium benzoate experiments contained 10 mm HEPES buffer, pH 7.0. In all bitter-taste experiments, no significant difference was found in the preference indexes between DGsα^R19/+ and cn bw/+ flies at any concentrations (p > 0.05). NS, Not significant. C, The amount of intake at 10, 20, 40, and 80 mm trehalose in DGsα^R19/+ flies (open columns) and the amount of intake at 40 and 80 mm trehalose in DGsα^R60/+ flies (shaded columns) was significantly lower than in cn bw/+ flies (filled columns). Asterisks indicate a statistical difference between the control and the heterozygous mutant (p < 0.05). D, The amount of intake at 20 and 40 mm trehalose in Gs27; DGsα^R19/+ flies (shaded columns) was not different from in cn bw/+ flies (filled columns, p > 0.05), but significantly higher than that in DGsα^R19/+ flies (open columns, asterisks, p < 0.05).