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. Author manuscript; available in PMC: 2017 Jul 1.
Published in final edited form as: Psychopharmacology (Berl). 2016 Apr 27;233(13):2479–2487. doi: 10.1007/s00213-016-4296-8

Figure 3.

Figure 3

Cumulative antinociceptive dose response curve for fentanyl ip in mouse warm water tail withdrawal assay before and after (A) 7 days of chronic 0.3 mg/kg/day fentanyl treatment sc (n=6) or 7 days chronic saline treatment sc (n=6) (B) 7 days of chronic 10 mg/kg/day VRP26 treatment sc (n=6) or 7 days chronic saline treatment sc (n=6). (C) Global withdrawal scores for animals treated for 7 days with either 0.3 mg/kg/day fentanyl (n=6), 10 mg/kg/day VRP26 (n=6), or saline (n=6) sc. Withdrawal was precipitated with 10 mg/kg naltrexone ip and jumps, wet dog shakes, paw tremor, soft stool, teeth chattering, and piloerection were all counted as physical symptoms of withdrawal. Data are plotted as mean +/− standard error of the mean (SEM) for all groups. * p< 0.05; **p< 0.01; **** p< 0.0001