Skip to main content
. Author manuscript; available in PMC: 2022 Apr 27.
Published in final edited form as: Pharmacol Biochem Behav. 2021 Jul 21;208:173242. doi: 10.1016/j.pbb.2021.173242

Fig. 3.

Fig. 3.

Schematic of the cumulative dose procedure for antinociceptive assessments of fentanyl-related substances following a 1 mg/kg, SC naltrexone (NTX) pretreatment (FEN; fentanyl used as example) in warm-water tail-withdrawal tests. Acute doses tested were 0.01, 0.09, 0.9, 2.2, and 6.8 mg/kg, SC fentanyl resulting in cumulative doses of 0.01, 0.1, 1.0, 3.2, and 10 mg/kg, SC fentanyl. “T X” indicates time in minutes following an injection of naltrexone.