Synergy between a NR2B receptor antagonist DHQ and 3-methyl-gabapentin in mice with neuropathic pain

The synergistic effect of a selective NR2B NMDA receptor antagonist, (−)-(R)-6-{2-[4-(3-Fluorophenyl)-4-hydroxy-1-piperidinyl]-1-hydroxyethyl-3,4-dihydro-2(1H)-quinolinone (DHQ), and a α2δ ligand, 3-methyl-gabapentin (3M-GBP), was investigated in the mouse partial sciatic nerve model. The interaction was observed after administration of DHQ and 3M-GBP combination at fixed dose ratios of 1:10 and 1:30 and the dose–response curves shifted approximately 13- and 17-fold leftward, respectively, from the theoretical additive values. However, a fixed dose ratio of 1:50 resulted only in an additive effect. These results indicate the synergistic interaction between DHQ and 3M-GBP in this animal model of neuropathic pain.