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. Author manuscript; available in PMC: 2023 Mar 27.
Published in final edited form as: Psychopharmacology (Berl). 2021 Mar 25;238(7):1885–1897. doi: 10.1007/s00213-021-05816-9

Figure 4. Effect of intraplantar CFA on fentanyl vs. food choice.

Figure 4.

(A) Experimental timeline of Experiment 3B. (B) Fentanyl choice: Percent fentanyl choice across within-session fentanyl unit doses in rats with an intraplantar injection of CFA (n=8). Left: Within-session fentanyl-vs.-food choice dose-response function on Days 1, 3, and 7 following intraplantar CFA administration. Right: Session percent fentanyl choice across the first 14 days following intraplantar CFA, averaged across fentanyl unit dose. (C) Reinforcement rates: Total choices completed per component (maximum of 10 choices per component) across the within-session reinforcement-rate dose-response function. Left: Within-session fentanyl-vs.-food choice dose-response function on Days 1, 3, and 7 following intraplantar CFA administration. Right: Total choices per session across the first 14 days following intraplantar CFA, averaged across fentanyl unit dose. (D) Confirmation of CFA inflammation: Left: Effect of intraplantar CFA on mechanical sensitivity (Threshold (log g) for paw withdrawal from von Frey filaments). Right: Effect of intraplantar CFA on paw width (mm). * Difference from baseline at a given timepoint, p<0.05. # Significant main effect of time since intraplantar CFA, p<0.05. Data are mean ±SEM.