Agonist responses at the wildtype and polymorphic variants of the β1-adrenoceptor.

Log EC50 values and % isoprenaline maximal responses obtained from 3H-cAMP accumulation in cells expressing either the human wildtype β1-adrenoceptor or the polymorphic variants. Values are mean ± s.e.mean of n separate determinations.One-way ANOVA with post hoc Neuman-Keuls was performed comparing the log EC50 values and % maximum isoprenaline responses obtained for the wildtype receptor with those obtained for each polymorphic variant in turn.# = pThe log EC50 values and % maximum isoprenaline responses for the partial agonists cimaterol, CGP 12177, nebivolol and xamoterol are significantly different for the Ser49/Arg389 receptor compared with wildtype. This could be due to either the higher receptor expression level of the Ser49/Arg389 cell line or more efficient receptor-effector coupling of the Ser49/Arg389 receptors (see Discussion for further detail).