SBCHM01-induced tolerance after systemic administration. SBCHM01 was injected i.v. at a dose of 4 mg/kg daily for 5 days. The results scored as %MPE were compared with morphine (i.p.) at the same dose. (A) The SBCHM01-mediated antinociception measured on the first day of the study; (B) Reduction of SBCHM01 analgesic activity on the fifth day of the experiment. Each column represents mean ± SEM of 8-10 mice. ***p < 0.001 significantly different from morphine-injected animals.