The antinociceptive effect of DPDPE and DAMGO at spinal level in naive and morphine-tolerant mice
| Pretreatment | AD50 of peptides (95% confidence limits) | |
|---|---|---|
| DPDPE | DAMGO | |
| nmol/mouse | ||
| Naive | 5.8 (3.7–8.9) | 0.06 (0.04–0.09) |
| Morphine pellet | 22 (15–32) | 0.11 (0.07–0.18) |