Skip to main content
. Author manuscript; available in PMC: 2020 Jun 1.
Published in final edited form as: Neuropharmacology. 2019 Mar 14;151:180–188. doi: 10.1016/j.neuropharm.2019.03.020

Figure 3.

Figure 3.

Effects of fentanyl (left panels) and methadone (right panels) on ICSS frequency-rate curves in rats before (top panels) and after (bottom panels) seven-day treatment with 0.032 mg/kg/day fentanyl or 1.0 mg/kg/day methadone, respectively. Abscissae: electrical brain stimulation frequency in Hertz (Hz, log scale). Ordinates: ICSS reinforcement rate expressed as a percentage of the maximum control rate (% MCR). Filled symbols indicate statistical significance (p<0.05) as compared to saline. All points show mean ± S.E.M. for n=6 rats.