a–c, AS408 (yellow symbols) modestly enhances inverse agonist ICI-118,551 inhibition of [3H]DHAP binding (a) while diminishing full agonist norepinephrine binding to β2AR wild type (wt) in the absence (b), or presence (c) of coexpressed Gs heterotrimer. d,e, AS408 displays inverse agonist activity on constitutive G-protein activation at high concentrations (d) but does not appear to enhance ICI-118,551 inhibition of [35S]GTPγS binding (e; inset, normalized). f, AS408 accelerates the dissociation of full agonist [3H]formoterol only on G-protein uncoupling in the presence of 10 μM GTPγS. Data are given as mean ± s.e.m. of 3–4 experiments done in duplicate. The sample size (n) is labeled in the figure.