Fig. 4.

Effects of TM5 serine mutations on potencies of catechol agonists. ΔpEC₅₀ values of cAMP accumulation for the S198A, S199A, and S202A D₁ receptor mutants relative to that for the wild-type receptor, were calculated from independent experiments performed in parallel. Data represent means and S.E.M for at least three matched experiments. The corresponding pEC₅₀ values were all significantly different from the wild-type value (p < 0.05; one-way ANOVA with Dunnett's post-test). A, ΔpEC₅₀ values at each mutant relative to the wild-type value, for the cyclohexyl-substituted isochroman (□), chroman (▩), and carbocyclic (■). *, p < 0.05; **, p < 0.01 significantly different from cyclohexyl chroman (one-way ANOVA with Dunnett's post-test). B, ΔpEC₅₀ values at each mutant relative to the wild-type value for dopamine, apomorphine, and DHX. C, ΔpEC₅₀ values at each mutant relative to the wild-type value for three phenylbenzazepine ligands.