Fig. 6.

Effects of 6 d repeated morphine (10 mg/kg, s.c.) treatment on horizontal locomotor activity of GluR-A−/− (B) and GluR-A(R/R) (D) mutant mice and their wild-type controls (A,C, respectively). The bars indicate means ± SEM (n = 10–14) for ambulatory activity counts after a morphine test dose of 3 mg/kg (subcutaneous), which normally induces no clear locomotor stimulation. The tests were performed first with naïve but habituated animals (Test1), then 24 hr (Test2), and then 5 d after the last morphine dose (Test3). In each mouse line, the treatment groups consisted of the control saline-treated group (injected twice per day with saline, once in home cages and once in locomotor activity cages), the unpaired morphine group (saline in activity cages and morphine in home cages), and the paired morphine group (morphine in activity cages and saline in home cages). *p < 0.05 for the difference from the corresponding saline control group; #p < 0.05 for the difference from the corresponding activity counts in test 1; Dunnett's test.