Figure 4
Naloxone-precipitated morphine-withdrawal responses in STEP+/+ and STEPC230X−/− mice. (a–h) Physical withdrawal symptoms in STEP+/+ and STEPC230X−/− mice. The number of jumps (a), paw tremors (b), sniffs (c) and wet-dog shakes (d) displayed were recorded during a 30-min period. Ptosis (e), teeth chattering (f), body tremor (g) and diarrhea (h) were evaluated over six 5-min periods. The number of periods in which the signs were observed were counted, and the maximum score was 6. (i) The global withdrawal score was calculated for each animal by giving each sign a relative weight. Data are expressed as the mean±s.e.m. Significant differences between saline-treated control and indicated groups at *P<0.05 and **P<0.01, respectively; Significant differences between morphine-treated STEP+/+ mice and morphine-treated STEP−/− mice at #P<0.05 and ##P<0.01, respectively (n=6–8 animals per group, one-way analysis of variance followed by Newman–Keuls multiple comparison test).
