【摘要】 目的　研究鞘内 (IT)吗啡对切口疼痛模型大鼠脊髓背角P物质 (SP)的影响。方法　雄性SD大鼠 16只 ,随机分为四组 (每组 4只 ) :假手术组 (组Ⅰ )、术前 30minIT 0 9%氯化钠 2 0 μl组(对照组 ,组Ⅱ )、术后 30minIT吗啡 5 μg组 (组Ⅲ )和术前 30minIT吗啡 5 μg组 (组Ⅳ )。按Brennan法制成切口疼痛模型 ,以累积疼痛评分确定疼痛行为。免疫组织化学方法观察脊髓背角SP免疫反应 (SP LI)。结果　组Ⅲ和组Ⅳ大鼠的累积疼痛评分均明显低于组Ⅱ (P <0 0 1)。组Ⅱ大鼠术侧脊髓背角浅层SP LI物质积分光密度明显高于组Ⅰ及对侧 (对照组 :0 6 2± 0 0 7,假手术组 :0 40±0 0 9,P <0 0 1) ;与组Ⅱ比较 ,组Ⅳ的大鼠术侧脊髓背角浅层SP LI物质积分光密度 (0 37± 0 0 6 )明显降低 (P <0 0 1) ,但两用药组间比较无显著差别。结论　在大鼠切口疼痛模型中 ,术前IT吗啡的抗伤害作用与其抑制SP在脊髓背角的释放有关更多还原

【Abstract】 Objective Substance P and its receptor are thought to play an important role in the mechanisms of pain The purpose of this study was to investigate the effects of intrathecal (IT) morphine on substance P expression in the dorsal horn of spinal cord in a rat model of incisional pain Methods Sixteen male SD rats weighing 250 300g were randomly divided into four groups of 4 animal each: in group Ⅰ (sham operation) 30 min after IT normal saline(NS) 20 μl 1 4% isoflurane was inhaled for 5 min but no incision was made; in group Ⅱ (control group) 30 min before incision NS 20 μl was given IT; in group Ⅲ (postoperative analgesia group) morphine 5 μg (10 μl) was given IT 30 min after incision; group Ⅳ ( preemptive analgesia group) morphine 5 μg (10 μl) was given IT 30 min before incision The animals were anesthetized with intraperitoneal pentobarbital sodium 40 mg·kg -1 PE 10 catheter was inserted intrathecally to the lumbar region according to method of Yaksh 5 days later incision of 1 cm long was made in the plantar region of left hindpaw parallel to the muscle under isoflurane anesthesia according to the method of Brennan Pain behavior was assessed by a cumulative pain score Immuno histochemistry technique was used to measure the expression of substance P Results IT morphine given either before or after incision decreased the cumulative pain scores Incision made in the plantar region of left hindpaw increased substance P expression in the ipsilateral dorsal horn of spinal cord (0 62±0 07 vs 0 40±0 09) In group Ⅳ increase in substance P expression in the dorsal horn of spinal cord was inhibited Conclusions The analgesia provided by preemptive IT morphine is possibly mediated via the decrease in substance P in the dorsal horn of spinal cord更多还原