LIM-Anestesiologia Experimental, Faculdade de Medicina, Universidade de São Paulo, Brasil.
Braz J Med Biol Res. 2012 Feb;45(2):147-52. doi: 10.1590/s0100-879x2011007500164. Epub 2011 Dec 23.
Local anesthetic efficacy of tramadol has been reported following intradermal application. Our aim was to investigate the effect of perineural tramadol as the sole analgesic in two pain models. Male Wistar rats (280-380 g; N = 5/group) were used in these experiments. A neurostimulation-guided sciatic nerve block was performed and 2% lidocaine or tramadol (1.25 and 5 mg) was perineurally injected in two different animal pain models. In the flinching behavior test, the number of flinches was evaluated and in the plantar incision model, mechanical and heat thresholds were measured. Motor effects of lidocaine and tramadol were quantified and a motor block score elaborated. Tramadol, 1.25 mg, completely blocked the first and reduced the second phase of the flinching behavior test. In the plantar incision model, tramadol (1.25 mg) increased both paw withdrawal latency in response to radiant heat (8.3 ± 1.1, 12.7 ± 1.8, 8.4 ± 0.8, and 11.1 ± 3.3 s) and mechanical threshold in response to von Frey filaments (459 ± 82.8, 447.5 ± 91.7, 320.1 ± 120, 126.43 ± 92.8 mN) at 5, 15, 30, and 60 min, respectively. Sham block or contralateral sciatic nerve block did not differ from perineural saline injection throughout the study in either model. The effect of tramadol was not antagonized by intraperitoneal naloxone. High dose tramadol (5 mg) blocked motor function as well as 2% lidocaine. In conclusion, tramadol blocks nociception and motor function in vivo similar to local anesthetics.
曲马多经皮给药后的局部麻醉效果已有报道。我们的目的是研究神经周围注射曲马多作为两种疼痛模型中唯一镇痛剂的效果。这些实验使用雄性 Wistar 大鼠（280-380 g；每组 N = 5）。在神经刺激引导的坐骨神经阻滞下，在两种不同的动物疼痛模型中，经神经周围注射 2%利多卡因或曲马多（1.25 和 5 mg）。在退缩行为测试中，评估退缩次数，在足底切口模型中，测量机械和热阈值。量化利多卡因和曲马多的运动效应，并制定运动阻滞评分。曲马多 1.25 mg 完全阻断了退缩行为测试的第一相，并减少了第二相。在足底切口模型中，曲马多（1.25 mg）增加了热辐射引起的足部退缩潜伏期（8.3 ± 1.1、12.7 ± 1.8、8.4 ± 0.8 和 11.1 ± 3.3 s）和对冯弗雷尔细丝的机械阈值（459 ± 82.8、447.5 ± 91.7、320.1 ± 120、126.43 ± 92.8 mN），分别在 5、15、30 和 60 分钟时。在两种模型中，假阻滞或对侧坐骨神经阻滞在整个研究过程中与神经周围生理盐水注射均无差异。曲马多的作用不能被腹腔内纳洛酮拮抗。高剂量曲马多（5 mg）阻断运动功能与 2%利多卡因相同。总之，曲马多在体内与局部麻醉药相似，可阻断伤害感受和运动功能。
