Figure 3.

Effects of the AT₁ receptor mutants on the inverse agonist activities of candesartan, telmisartan and eprosartan in cells expressing various mutants of WT‐AT₁ receptors, as measured by the IP assay. The inverse agonist activities of (A) candesartan, (B) telmisartan and (C) eprosartan at a concentration of 10 μM for each ARB in COS‐1 cells transfected with WT‐AT₁ receptors, single mutants and double mutants are shown. The double mutants were constructed using two independent mutants that significantly attenuated the inverse agonist activity. The inverse agonist activities are expressed as a percentage of the constitutive activity of either WT‐AT₁ receptors or each mutant. The constitutive activities of the vehicle‐treated cells expressing WT‐AT₁ receptors and each mutant were defined as 0% for each. Data represent mean ± SEM of independent experiments [candesartan: n = 8 (WT‐AT₁ receptor) and n = 6 (all mutants); telmisartan: n = 12 (Y292A), n = 10 (WT‐ AT₁ receptor, E173A and Q257A), n = 8 (N295A) and n = 6 (all other mutants); and eprosartan: n = 12 (WT‐ AT₁ receptor), n = 10 (E173A, Q257A, Y292A and N295A) and n = 6 (all other mutants)]. Group sizes are not equal in Figure 3. The reason for this is that data of some groups showed large SEM when n = 6 per group, and we had to examine additional experiments to confirm exact value for these groups. ^* P < 0.05, significant difference from WT‐ AT₁ receptors †, additive effect; one‐way ANOVA followed by Bonferroni's or Dunnett's post hoc tests.