Buprenorphine hydrochloride (Sigma, St. Louis, MO), norbinaltorphimine (nor-BNI;
Tocris Bioscience, Ellisville, MO), desipramine hydrochloride (DMI; Sigma), and U50,488
(Sigma) were dissolved in distilled water and injected intraperitoneally (i.p.). Morphine
(Spectrum Chemical, New Brunswick, NJ) was diluted in 0.9% saline and injected
i.p. Mice in the control groups were injected with 0.9% saline. All doses were
calculated according to the base weight of the drug and administered in a volume of 10
ml/kg.
Tocris Bioscience, Ellisville, MO), desipramine hydrochloride (DMI; Sigma), and U50,488
(Sigma) were dissolved in distilled water and injected intraperitoneally (i.p.). Morphine
(Spectrum Chemical, New Brunswick, NJ) was diluted in 0.9% saline and injected
i.p. Mice in the control groups were injected with 0.9% saline. All doses were
calculated according to the base weight of the drug and administered in a volume of 10
ml/kg.
