Table 2.
Emax and pEC50 values of several 5-HT6 receptor ligands for inducing cAMP formation in stably transfected HEK-293F/rat 5-HT6 cells in either absence or copresence of forskolin, and corresponding pKi values
| cAMP formation | |||||
|---|---|---|---|---|---|
| Forskolin (1 μm) | w/o | + | 5-HT6 receptor binding | ||
| Compound | Emax (pmol 106 cells−1) | pEC50 | Emax (pmol 106 cells−1) | pEC50 | pKi |
| 5-HT | 17.4±0.8 | 7.29±0.21 | 27.6±0.7a | 8.23±0.12b,c | 6.96±0.18 |
| E-6801 | 12.7±0.5 | 8.02±0.23 | 24.5±0.6a | 9.58±0.15b,c | 8.46±0.13 |
| E-6837 | 7.1±0.7 | 6.52±0.91d | 21.5±0.7a,e | 8.85±0.23b | 9.13±0.17 |
| Ro 04-6790 | 5.3±1.3 | <5 | 7.3±0.6 | <5 | 6.91±0.04 |
| SB-271046 | 5.2±0.5 | <5 | 5.9±0.5 | <5 | 8.68±0.09 |
| Basal | 5.8±0.4 | — | 7.0±0.4 | — | |
Emax and pEC50 values were derived from cAMP-mediated agonist curves as illustrated in Figure 3. Data correspond to mean±s.e.m. values of five to six independent experiments performed in duplicate. pKi values for h5-HT6 receptor were obtained as described in Methods. a: P<0.001 versus Emax w/o forskolin; b: P<0.001 versus pEC50 w/o forskolin; c: P<0.01 and d: P<0.001 versus pKi value; e: P<0.05 versus Emax 5-HT with forskolin.