Table 2.
Summary of EC50 and Emax values of KOR agonists for G protein activation as measured by GloSensor cAMP assay and G protein independent β-arrestin recruitment as measured by Tango assay. The prototypic selective KOR agonist U50,488H was used as the balanced agonist. Emax values in the GloSensor assay denote the maximal degree of inhibition. Data were derived from the curves in Figure 3. Mean ± SEM (n = 3). EC50 and Emax data of GloSensor cAMP and Tango assays were analyzed with one-way ANOVA followed by Tukey’s post-hoc test, respectively. Results of one-way ANOVA are: Emax of GloSensor cAMP assay: F (2,6) = 2.77, p > 0.05; EC50 of GloSensor cAMP assay: F (2,6) = 22.91, p < 0.01; Emax of Tango assay: F (2,6) = 28.32, p < 0.001;
| GloSensor cAMP assay | Tango assay | |||||
|---|---|---|---|---|---|---|
| EC50(nM) | Emax(%) | N | EC50(nM) | Emax | N | |
| U50,488H | 1.61±0.19 | 72.95±0.86 | 3 | 1.43±0.13 | 99.93±0.07 | 3 |
| Nalfurafine | 0.17±0.04** | 69.82±1.53 | 3 | 0.74±0.07 | 108.0±2.6* | 3 |
| 42B | 0.82±0.18* | 74.40±1.68 | 3 | 3.22±0.42**,## | 116.8±1.0***,# | 3 |
EC50 of Tango assay: F (2,6) = 24.80, p < 0.01. Significance levels are
p < 0.05,
p < 0.01,
p < 0.001, compared with U50,488H in the same assay;
p < 0.05,
p < 0.01, compared with nalfurafine in the same assay, by Tukey’s post-hoc test.