Effect of various 5-HT receptor ligands on [35S]GTPγS (0.2 nM) binding to membranes of Sf9 cells coexpressing the h5-ht5A receptor and G protein subunits of the Gi/ofamily
| Compound | Sf9 cells Expressing the h5-ht5A Receptor+ | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gαi1+ Gβ1γ2 | Gαi2 + Gβ1γ2 | Gαi3 + Gβ1γ2 | Gαo + Gβ1γ2 | |||||||||
| pEC50 | Emax | n | pEC50 | Emax | n | pEC50 | Emax | n | pEC50 | Emax | n | |
| −logM | % | −logM | % | −logM | % | −logM | % | |||||
| 5-CT | 7.6 ± 0.2 | 98 ± 12 | 3 | 7.6 ± 0.2 | 91 ± 17 | 3 | 7.9 ± 0.1 | 98 ± 16 | 3 | 8.0 ± 0.0 | 98 ± 1 | 2 |
| 5-MT | 6.5 ± 0.1 | 98 ± 17 | 3 | 6.4 ± 0.1 | 91 ± 17 | 3 | 6.9 ± 0.2 | 94 ± 12 | 3 | 7.2 ± 0.0 | 88 ± 4 | 2 |
| DHE | 7.3 ± 0.5 | 46 ± 7 | 3 | 7.0 ± 0.2 | 44 ± 8 | 3 | 7.0 ± 0.1 | 46 ± 19 | 3 | 7.4 ± 0.3 | 82 ± 9 | 3 |
| LSD | 8.5 ± 0.2 | 64 ± 23 | 3 | 8.4 ± 0.2 | 55 ± 14 | 3 | 8.2 ± 0.2 | 58 ± 1 | 3 | 7.9 ± 0.9 | 93 ± 4 | 3 |
| pIC50-corr | I max | n | pIC50-corr | I max | n | pIC50-corr | I max | n | pIC50-corr | I max | n | |
| DHE | 8.0 ± 0.1 | 64 ± 7 | 3 | 8.0 ± 0.1 | 65 ± 7 | 3 | 8.2 ± 0.1 | 62 ± 8 | 3 | 8.8 ± 0.1 | 13 ± 7 | 2 |
| LSD | 9.0 ± 0.2 | 52 ± 13 | 3 | 9.0 ± 0.2 | 56 ± 11 | 3 | 9.1 ± 0.4 | 44 ± 3 | 3 | 9.1 ± 0.5 | 17 ± 13 | 3 |
| Methiothepin | 8.9 ± 0.5 | 111 ± 6 | 3 | 8.9 ± 0.5 | 110 ± 3 | 3 | 9.2 ± 0.0 | 110 ± 4 | 3 | 9.1 ± 0.2 | 123 ± 2 | 3 |
[35S]GTPγS binding studies were performed on membranes as described in Experimental Procedures. pEC50 and pIC50 values were derived from the curves.Emax values and Imax values were calculated, and pIC50 values were corrected into pIC50-corr values as described under Experimental Procedures. The results are mean ± S.D. values fromn independent experiments.