Effect of guanosine 5′-(β,γ-imido)triphosphate on [3H]diprenorphine binding in mMOR-1 and mMOR-1B4
[3H]Diprenorphine binding was performed in membranes from the stably transfected CHO cells with or without 1 00 μM GppNHp. Ki values were determined from at least three independent determinations. Student's t test was used to compare the Ki values between the groups with and without GppNHp for each drug.
| mMOR-1 | mMOR-1B4 | |||||
|---|---|---|---|---|---|---|
| Control | With Gpp(NH)p | Shift | Control | With Gpp(NH)p | Shift | |
| nM | ||||||
| Morphine | 104.3 ± 2.2 | 147.8 ± 8.1* | 1.4 | 296 ± 21 | 949 ± 29** | 3.2 |
| DAMGO | 55.5 ± 1.3 | 82.8 ± 10.8 | 1.5 | 343 ± 161 | 908 ± 304 | 2.6 |
| Etorphine | 0.49 ± 0.06 | 0.55 ± 0.04 | 1.1 | 2.1 ± 0.4 | 4.6 ± 0.6 | 2.2 |
| Fentanyl | 53.6 ± 4.0 | 89.3 ± 7.4 | 1.7 | 446 ± 130 | 659 ± 56 | 1.5 |
| Naloxone | 15.4 ± 1.6 | 14.1 ± 0.7 | 0.9 | 20.9 ± 1.1 | 37.3 ± 10.9 | 1.8 |
| CTAP | 3.7 ± 0.5 | 2.1 ± 0.4** | 0.6 | 8.9 ± 3.1 | 10.8 ± 5.8 | 1.2 |