Effects of Brugmansia arborea Extract and Its Secondary Metabolites on Morphine Tolerance and Dependence in Mice
Figure 3
Effects of single alkaloids on the expression (a) and the acquisition (b) of tolerance to morphine-induced analgesia. Mice were treated twice daily for 5 days with either saline or 10 mg/kg morphine. Atropine (2.2 mg/kg), apoatropine (1.8 mg/kg) and 3-tigloyl-oxitropane (1.5 mg/kg) were administered 30 min before each morphine injection (acquisition) or prior to the last morphine treatment (expression). Morphine antinociceptive effect (%MPE) was assessed on day 1 and day 5, as indicated. Significant differences: **, compared to control group; ++, compared to related-morphine group on day 1.
