Table 1.
Agonist activity on Gαi1 and Gαo interaction of D2 ligands
Agonist-induced Gαi1 or Gαo interaction with D2 is shown. Efficacy (Emax) is relative to the maximum effect of dopamine (=100%). Bias factor was calculated as described under “Experimental procedures.” Values in parentheses indicate S.E.
| Ligand | Gi1 |
Go |
Bias factor, ΔΔlog (Emax/EC50) | ||
|---|---|---|---|---|---|
| pEC50 | Emax | pEC50 | Emax | ||
| % | % | ||||
| Dopamine | 8.64 (0.10) | 100 | 6.60 (0.05) | 100 | 0 (0.12) |
| Apomorphine | 8.25 (0.04) | 103 | 6.62 (0.04) | 63 | −0.27 (0.03) |
| Piribedil | 8.28 (0.04) | 112 | 6.76 (0.14) | 42 | −0.12 (0.18) |
| Pramipexole | 8.59 (0.07) | 119 | 6.80 (0.09) | 77 | 0.04 (0.17) |
| Ropinirole | 8.23 (0.06) | 106 | 5.89 (0.08) | 73 | 0.41 (0.12) |
| Pergolide | 10.13 (0.07) | 100 | 8.26 (0.07) | 54 | 0.09 (0.18) |