Fig. 1. (A ) Acute paw-pressure responses (mean ± SEM) to saline, morphine, gabapentin, and morphine plus gabapentin. All doses of morphine and gabapentin are 7.5 mg/kg and 150 mg/kg, respectively. *P < 0.05 versus saline; +P < 0.05 versus morphine. (B ) Acute tail-flick responses (mean ± SEM) to saline, morphine, gabapentin and morphine plus gabapentin. All doses of morphine and gabapentin are 7.5 mg/kg and 150 mg/kg, respectively. *P < 0.05 versus saline; +P < 0.05 versus morphine.