The Ehrlich Tumor Induces Pain-Like Behavior in Mice: A Novel Model of Cancer Pain for Pathophysiological Studies and Pharmacological Screening
Figure 6
Effect of morphine treatment on pain and paw edema/tumor growth induced by the Ehrlich tumor cells. Mice that received the 1 × 106 Ehrlich tumor cells were treated with morphine (1–10 mg/Kg, i.p.) or saline on the 8th day after tumor cells injection. (a) The intensity of mechanical hyperalgesia, (b) thermal hyperalgesia, and (c) paw edema/tumor growth was evaluated 45 minutes after treatment with morphine. In another set, mice were treated with naloxone (1 mg/kg, i.p.) 1 hour before the treatment with morphine (10 mg/kg i.p.), and (d) 45 minutes after morphine treatment, the intensity of mechanical hyperalgesia and (e) thermal hyperalgesia was evaluated. Mice received the 1 × 107 Ehrlich tumor cells or saline, and after 8 days, they were treated with naloxone (1 mg/kg i.p.) 1 h before treatment with morphine (10 mg/kg i.p.), and (f) 45 min after the treatment with morphine, the overt pain was assessed; , representative of two experiments. * vehicle group compared with the saline; # compared with the tumor or compared with the treatment with naloxone plus morphine, and ** compared with the doses of 1 and 3 mg/kg morphine.
