Fig. 2. (A ) Paw-pressure responses (mean ± SEM) to chronic saline, morphine, and morphine plus gabapentin (gabapentin given for days 1–7; days 5–7; or days 1–3). All doses of morphine and gabapentin are 15 mg/kg and 150 mg/kg, respectively. *P < 0.05 versus saline; +P < 0.05 versus morphine. (B ) Tail-flick responses (mean ± SEM) to chronic saline, morphine, and morphine plus gabapentin (gabapentin given on days 1–7; days 5–7; or days 1–3). All doses of morphine and gabapentin are 15 mg/kg and 150 mg/kg, respectively. *P < 0.05 versus saline; +P < 0.05 versus morphine.