Fig. 2.
Locally and systemically administered loperamide–oxymorphindole synergizes in naïve animals. (A) Dose–response curves showing the ability of intraplantar loperamide, oxymorphindole or their combination (1:1) to inhibit nociceptive responses in the Hargreaves assay (n = 6 per dose). Data are shown as % MPE ± SD. (B) Isobolographic analysis of the data from A, showing a synergistic interaction. (C) Dose–response curves for subcutaneous loperamide, oxymorphindole, or their combination (1:1; n = 5 per dose). Data are shown as % MPE. (D) Isobolographic analysis of the data from C, demonstrating a synergistic interaction. **P < 0.01, ****P < 0.0001. i.pl., intraplantar; MPE, maximum possible effect; s.c., subcutaneous.