TABLE 5.
Drug effects on radioligand binding to dopamine D1, D2, D3, and D4.4 receptors
For each receptor, a standard agonist (SKF38393 or quinpirole) and antagonist (SCH23390, butaclamol, or haloperidol) was tested.
| Drug | DA D1R | DA D2R | DA D3R | DA D4.4R |
|---|---|---|---|---|
| [3H]SCH 23390 | [3H]Spiperone | [3H]Spiperone | [3H]Spiperone | |
| Ki (nM) ± S.E.M. (n) | Ki (nM) ± S.E.M. (n) | Ki (nM) ± S.E.M. (n) | Ki (nM) ± S.E.M. (n) | |
| Hill Slope ±S.E.M. | Hill Slope ±S.E.M. | Hill Slope ±S.E.M. | Hill Slope ±S.E.M. | |
| Fentanyl | 1670 ± 200 (3) | 14,900 ± 1800 (3) | 12,100 ± 910 (5) | 1049 ± 74 (3) |
| −1.17 ± 0.07 | −1.20 ± 0.06 | −0.88 ± 0.11 | −1.13 ± 0.02 | |
| Morphine | >100 µM (3) | >100 µM (3) | >100 µM (3) | >100 µM (3) |
| ND | ND | ND | ND | |
| SKF38393 | 79 ± 12 (3) | |||
| −1.03 ± 0.04 | ||||
| SCH23390 | 0.159 ± 0.018 (3) | |||
| −1.16 ± 0.03 | ||||
| Quinpirole | 15,700 ± 4900 (6) | 130 ± 20 (6) | 157.4 ± 7.8 (3) | |
| −0.79 ± 0.08 | −0.73 ± 0.03 | −0.80 ± 0.01 | ||
| Butaclamol | 0.58 ± 0.13 (7) | 8.2 ± 3.5 (6) | ||
| −0.83 ± 0.18 | −1.15 ± 0.30 | |||
| Haloperidol | 4.60 ± 0.27 (3) | |||
| −0.98 ± 0.01 |
n, number of independent experiments, each conducted with duplicate determinations; ND, not determined.