Sigmoidal isotherms for h5-HT1A receptor-mediated stimulation of [35S]GTPγ S binding to Gαi3 subunits
| Ligand | pEC50/pIC50 | Emax/Emin | n | pKi |
|---|---|---|---|---|
| % | ||||
| Agonists | ||||
| S15535 | 8.91 ± 0.08 | 234 ± 16 | 3 | 9.10 |
| (−)-Pindolol | 8.24 ± 0.03 | 193 ± 10 | 5 | 8.19 |
| WAY100,635 | 8.52 ± 0.06 | 135 ± 5 | 3 | 9.25 |
| p-MPPI | 8.32 ± 0.07 | 128 ± 5 | 3 | 9.00 |
| (−)-UH301 | 8.24 ± 0.23 3-a | 111 ± 1 3-a | 2 | 7.87 |
| Inverse agonists | ||||
| Methiothepin | 7.84 ± 0.18 | 80 ± 2 | 3 | 8.08 |
| (+)Butaclamol | 6.47 ± 0.22 | 72 ± 3 | 3 | 6.40 |
| Haloperidol | 5.55 ± 0.14 | 69 ± 18 | 3 | 5.72 |
| Spiperone | 7.33 ± 0.07 | 27 ± 3 | 7 | 7.00 |
Activation of Gα i3 G-protein subunits in CHO-h5-HT1A cell membranes was determined employing an antibody-capture/SPA detection technique. Data are expressed as mean ± S.E.M. of n independent determinations performed in duplicate. For comparison, ligand affinity (pK i) is shown, as determined by competition binding with [3H]8-OH-8DPAT (Newman-Tancredi et al., 2001a,b).
pEC50, agonist concentration inducing half-maximal stimulation; pIC50, inverse agonist concentration inducing half of the inhibitory effect; E max, maximal observed agonist stimulation relative to specific basal binding (100%); E min, maximal inverse agonist inhibition of [35S]GTPγ S binding relative to specific basal binding (100%).
↵3-a Mean ± range.