Figure 4.
Effects of naloxone (Nlx) administration (1 mg kg−1, s.c.) alone or in combination with SR 141716A (10 mg kg−1 i.p., administered 2 h before naloxone injection) on physical withdrawal signs in mice (n=10 per group) chronically treated for 5 days with morphine (M) (from 20 to 100 mg kg−1, i.p.), or vehicle (V). Each animal received two injections daily. The results are expressed as means±s.e.mean of the number of events counted during the 40 min period of observation immediately after naloxone injection. ★P<0.05, ★★P<0.01 vs V/Nlx group; ⋆P<0.05, ⋆⋆P<0.01 vs V/SR+Nlx group.