Fig. 2. The effect of chronic gabapentin treatment on proportions of wide-dynamic-range (WDR) and nociceptive specific (NS) neurones in the superficial dorsal horn (SDH) of MRMT-1 injected rats. In sham-operated animals the ratio of WDR:NS was 26%:74% (n = 33 cells), which changed in MRMT-1 treated animals (n = 28 cells) to 47%:53%.  14 In MRMT-1 injected rats receiving gabapentin treatment (twice-daily subcutaneous injections of gabapentin 30 mg/kg on postoperative days 11–14 and a single injection on day 15), characterization of SDH neurones on day 15 (n = 30 cells), when pain-related behavior was returned to a normal (  i.e, sham-operated rat) degree, revealed a WDR:NS ratio of 33%:67%, approaching the normal ratio seen in sham-operated animals. Characterization on postoperative day 18 (n = 32 cells), 2 days after cessation of gabapentin treatment when animals had returned to the same degree of pain behavior as saline-treated rats revealed a return to the characteristic cancer-induced bone pain state with a WDR:NS ratio of 50%:50%.