ABSTRACT
BACKGROUND: Tissue injury by surgical manipulation or trauma may cause pain hypersensitivity secondary to central sensitization. The aim of this study was to evaluate the postoperative effect of gabapentin on incisional pain in rat pretreated with pentylenetetrazole. METHODS: Thirty rats were divided into 5 groups, a control group (n = 10), PTZ 10 group (n = 5), PTZ 20 group (n = 5), PTZ 30 group (n = 5), and a PG 30 group (n = 5). To evaluate postoperative mechanical hyperalgesia in injured feet, withdrawal thresholds were measured by calibrated von Frey filaments at 2 hr, 1 day, 2 days, 3 days, 4 days, and 5 days after the incision. RESULTS: The PTZ 10, 20, and 30 groups showed no significant difference in withdrawal thresholds when compared with the control group during 5 days postoperatively. There were no significant differences in withdrawal thresholds among the PTZ 10, 20, and 30 groups. However, the PG 30 group showed a significantly lower withdrawal threshold compared with the control group at postoperative days 3, 4 (p < 0.05), and 5 (p < 0.01). CONCLUSIONS: Intraperitoneal pentylenetetrazole administered before an incision had no effect on postoperative pain in the incisional pain model. However, gabapentin injection after an incision in rats pretreated with pentylenetetrazole caused hyperalgesia during 5 days postoperatively.