PolyMorphine and free morphine induce constipation and hyperactivity. (a) Mice
treated with 200 mg/kg of PolyMorphine (n = 6) or 10 mg/kg of free morphine (n = 8)
show constipation effects at 3-h post-injection compared to control animals (n = 6),
with no effects one to three days post-injection. (b) Mice treated with 200 mg/kg of
PolyMorphine (n = 6) show hyperactivity at one-day post-injection with no effects
3-h or two to three days post-injection compared to vehicle-treated animals (n = 6).
Mice treated with 10 mg/kg of free morphine (n = 8) show hyperactivity at 3-h
post-injection with no effects one to three days post-injection compared to
vehicle-treated animals. Constipation—two-way ANOVA, overall main effect of
treatment *P = 0.0385, overall main effect of time, ***P < 0.0001; Bonferroni
post hoc tests compared to vehicle, **P < 0.01. Hyperactivity—two-way ANOVA,
overall main effect of treatment, P = 0.1275; overall main effect of time,
***P < 0.0001; Bonferroni post hoc tests compared to vehicle, *P < 0.05 and
***P < 0.0001.