术前应用地佐辛对瑞芬太尼诱发早期痛觉过敏大鼠模型的抑制效应

Inhibitory effects of dezocine injection before surgery on remifentanil-induced hyperalgesia during early stage in a rat model

目的在瑞芬太尼诱发术后2h痛觉过敏大鼠模型中，探讨术前应用地佐辛抑制痛觉过敏的效果及机理。方法制备瑞芬太尼痛觉过敏模型：将大鼠分为切口组（I）和切口加瑞芬太尼组（IR），分别泵人生理盐水和瑞芬太尼（1．3μg·kg。·min-1），同时行切口手术。模型成功后将大鼠随机分为A、B、C、D、E5组，分别给予生理盐水、x受体激动剂U50488、小剂量”受体拮抗剂CTOP、U50488加小剂量CTOP和地佐辛，建立痛觉过敏模型。于术前、术后2h测量各组大鼠热缩足反射潜伏期（PWTL），检测脊髓强啡肽表达。结果（1）PWTL：与I组相比，IR组明显缩短（P〈0．05）；与A组相比，B、C、D、E组延长（P〈0．05）；与B、C组相比，D、E组延长（P〈0．05）；D、E组无统计学差异（P〉0．05）。（2）强啡肽：与A、C组相比，B、D、E组均增加（P〈0．05）；I、IR组之间，A、c组之间，B、D、E组之间比较差异均无统计学意义（P〉0．05）。结论持续泵人瑞芬太尼在术后2h诱发了痛觉过敏；地佐辛通过两方面协同抑制痛觉过敏：一方面拮抗部分”受体，另一方面激动x受体促进内源性强啡肽表达增加。

Objective To discuss the inhibitory effects and possible mechanism of dezocine injection before surgery in the rats model of remifentanil-induced hyperalgesia at 2 h after the surgery. Methods The rat model of remifentanil-induced hyperalgesia was established. Rats were divided into group I and group IR, then normal saline and remifentanil（1.3 btg.kg-1. min-1） were pumped respectively, meanwhile incision was operated. The rats were randomly divided into groups A, 13, C, D and E after finishing the model successfully. Normal saline, kappa receptor agonist U50488, low- dose mu receptor antagonist CTOP, U50488 plus low-dose CTOP and dezocine were injected respec- tively in each group before the surgery. Then the model of hyperalgesia was established. Paw with- drawal thermal lateney（PWTL） to noxious thermal stimulation was measured before and at 2 h after surgery. The expression of dynorphin in spinal cord was detected. Results （1） PWTL：Compared with group I, it was significantly decreased in group IR; Compared with group A, it was increased in group t3, C, D and E （P〈0.05） ; Compared with group 13 and C, it was increased in group D and E （P〈0.05） ;There was no significant!.y difference in PWTL between group D and E（P〈0, 05 ）. （2） The expression of dynorphin： Compared with group A and C, it was increased in group B, D and E （P〈0.05） ;There was no significantly differences in the expression of dynorphin between group I and IR, group A and C, group I-3,D and E （P〉0.05）. Conclusion Continuous pumping remifen- tanil can induce hyperalgesia at 2 h after the surgery; Dezocine can synergistic inhibit remifentanil-induced hyperalgesia at 2 h after surgery through these two ways, on one hand, it partly blocks the activity of mu receptor, on the other hand, it activates kappa receptor to increase the expression of dynorphin.