Efficacies (Emax values) and potencies (pEC50 or pKb values) of antiparkinson agents at recombinant h5-HT2A, h5-HT2B, and h5-HT2C receptors
| Ligand | h5-HT2A | h5-HT2B | h5-HT2C | |||
|---|---|---|---|---|---|---|
| Emax | pEC50 orpK b | Emax | pEC50orpK b | Emax | pEC50or pK b | |
| Apomorphine | 0 | 6.43 | 0 | 6.18 | 0 | 6.06 |
| Bromocriptine | 69 ± 11 | 8.15 | 0 | 8.89 | 79 ± 9 | 6.95 |
| Cabergoline | 94 ± 4 | 8.11 | 123 ± 2 | 8.59 | 96 ± 10 | 6.72 |
| Lisuride | 52 ± 4 | 8.09 | 0 | 8.96 | 75 ± 6 | 8.11 |
| Piribedil | 0 | <4 | 0 | 5.99 | 0 | <4 |
| Pergolide | 103 ± 10 | 8.79 | 113 ± 11 | 8.22 | 87 ± 4 | 7.35 |
| Roxindole | 0 | 7.70 | 0 | 7.28 | 0 | 5.78 |
| Terguride | 49 ± 10 | 7.62 | 0 | 7.75 | 0 | 6.10 |
Efficacy (Emax) and potency (pEC50) values at h5-HT2A, h5-HT2B, and h5-HT2C receptors were determined by [3H]PI depletion. The pEC50 indicates stimulation of [3H]PI depletion by the drug alone, and the pKb blockade of 5-HT-induced [3H]PI depletion. Emax values are percentages of the effect observed with a maximally efficacious concentration (10 μM) of serotonin and are expressed as means ± S.E.M. values of at least three independent determinations performed in triplicate. pEC50or pKb values are means of at least three independent determinations with S.E.M. values of less than 0.2 log units. Serotonin exhibited pEC50 values of 7.52, 8.52, and 8.87 at h5-HT2A, h5-HT2B, and h5-HT2C receptors, respectively.