Figure 5

EphB1 receptor knockout attenuates behavioral signs of morphine withdrawal. A-I: Behavioral signs of naloxone-precipitated morphine withdrawal in EphB1+/+ (wild-type, WT) and EphB1-/- (EphB1 knockout) mice. Those mice were injected (i.p.) with repeated pulses of morphine given in 7 escalating doses every 8 h (20, 40, 60, 80, 100, 100, and 100 mg/kg). Two hours after the last morphine injection, mice were injected with naloxone (1 mg/kg, s.c.), and withdrawal symptoms were monitored for 30 min after naloxone administration. J: Overall withdrawal score. In addition to measuring individual withdrawal signs (A-I), an overall opiate withdrawal score was calculated as (no. of backward walking steps × 0.1) + (diarrhea × 2) + (no. of jumps × 0.1) + (paw tremor × 0.1) + (ptosis) + (tremor) + (% weight loss × 5) + (no. of wet-dog shakes) as described in the Methods. The numbers of mice in each group are shown in parentheses in A-J (the ten mice in each group of EphB1+/+ and EphB1-/- through A-J were the same mice). **, p < 0.01, indicate significant differences compared with the WT control group.