Mean dose and 95% CL for morphine, cocaine, and amphetamine in shifting the naltrexone dose-effect curve 2-fold to the right during morphine treatment and mean ED50 and 95% CL for the same drugs in attenuating the naltrexone-like discriminative stimulus effects of acute morphine withdrawal
Drug | Morphine Treatment Dose Shifting Naltrexone Dose-Effect Curve 2-Fold Rightward | Acute Morphine Deprivation ED50 in Attenuating Naltrexone-Lever Responding | ||||
|---|---|---|---|---|---|---|
| mg/kg | 95% CL | mg/kg | 95% CL | |||
| Morphine | 3.24 | (0.97-10.83) | 1.11 | (0.52-2.34) | ||
| Cocaine | 1.04 | (0.82-1.34) | 0.36 | (0.15-0.65) | ||
| Amphetamine | 0.16 | (0.02-1.19) | 0.58 | (0.13-1.33) | ||
| Imipramine | 7.34 | (0.37-145.51) | N.A.a |
| ||
↵ a Not applicable; did not decrease naltrexone-lever responding to less than 50% after acute morphine withdrawal