The in vitro profile of loperamide, morphine, and DAMGO at cloned human opioid receptors
| Compound | Ki | Receptor Selectivity | μ-Opioid Receptor | ||||
|---|---|---|---|---|---|---|---|
| μ | δ | κ | μ/δ | μ/κ | EC50GTPγS | IC50 cAMP | |
| nM | nM | nM | |||||
| Loperamide | 3.3 ± 1.6 (3) | 48 ± 6 (4) | 1156 ± 124 (3) | 15 | 350 | 19 ± 1.1 (7) | 27 ± 6 (3) |
| Morphine | 19.3 ± 4.3 (4) | 171 ± 55 (4) | 273 ± 56 (3) | 9 | 14 | 115 ± 1.4 (7) | N.D. |
| DAMGO | 17.9 ± 2.1 (25) | >10,000 (2) | >10,000 (3) | >559 | >559 | 234 ± 1.3 (7) | N.D. |
Data are mean ± S.E.M., with the number of determinations given in parentheses.
N.D., not determined.