Figure 3.

Behavioral and pharmacokinetic results in vaccinated and unvaccinated mice administered carfentanil or fentanyl. Baseline nociception was measured, then mice received two consecutive intraperitoneal 200 μg/kg bolus doses of carfentanil, t = 0 and t = 15 min, and latency to nociception was measured at 15 min intervals in the hot plate (A) and tail flick (B) tests. Significance is denoted by an asterisk from a two-way RM ANOVA with Bonferroni’s post hoc test when comparing vaccinated groups to unvaccinated (control), *P < 0.05, **P < 0.01, ***P < 0.001 versus control. Mice were dosed with 20 μg/kg of carfentanil, then trunk blood (C) and the brain (D) were harvested 15 min postinjection and carfentanil was quantified by LCMS analysis. **P < 0.01 and ***P < 0.001 versus control determined by one-way ANOVA. Mice were cumulatively dosed with fentanyl, and latency to nociception was measured by hot plate (E) and tail flick (F) tests. (G) Calculated ED₅₀ values for fentanyl antinociception activity. Statistical comparison was made by one-way ANOVA with a Tukey’s post hoc test, ***P < 0.001 versus control group; ^#P < 0.05, ^#P < 0.01 versus other vaccine group. (H) Potency ratios determined for each vaccine group relative to the control group. Dashed line denotes control level. ^#P < 0.05 two-tailed t-test. Bars denote means ± SEM in all plots; n = 6 per group for all studies.