Fig. 5. Sedative effects of buprenorphine, norbuprenorphine, buprenorphine-3-glucuronide, and norbuprenorphine-3-glucuronide. The effect of buprenorphine, norbuprenorphine, buprenorphine-3-glucuronide, and norbuprenorphine-3-glucuronide on locomotion was quantified in an open-field test. A single mouse was habituated to the test room, administered vehicle or buprenorphine (0.3 mg/kg; 0.6 μmol/kg), norbuprenorphine (1 mg/kg; 1.2 μmol/kg), buprenorphine-3-glucuronide (1 mg/kg; 0.6 μmol/kg), or nor buprenorphine-3-glucuronide (2.2 mg/kg, 3.8 μmol/kg) and placed in a test chamber. Total activity was recorded by photobeam breaks for 1 h. Each result is the mean ± SD (n = 4 per group). Asterisk , significantly different from control sample (P < 0.05) by one-way ANOVA.