Kamerman Peter, Koller Anthony, Loram Lisa
Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa.
Pharmacology. 2007;80(4):244-8. doi: 10.1159/000104878. Epub 2007 Jul 6.
BACKGROUND/AIMS: Using a new animal model of postoperative pain we recently developed, we investigated whether the selective cyclooxygenase-2 (COX-2) inhibitor parecoxib sodium, and the analgesic tramadol hydrochloride, attenuated mechanical primary hyperalgesia induced by minor surgery on the rat tail.
For surgery, rats were anesthetized with isoflurane, a 20-mm-long incision was made through the skin and fascia of their tails, and the wound was sutured. Immediately after surgery, rats were injected intraperitoneally with parecoxib sodium (10 or 20 mg x kg(-1)), tramadol hydrochloride (10 mg x kg(-1)), or sterile saline (0.1 ml x kg(-1)). Hyperalgesia was assessed by measuring rats' response latencies to a blunt noxious mechanical stimulus (4 N) applied to their tails. Nociceptive testing was performed before surgery and 90 min after surgery.
Hyperalgesia was present in all saline-injected animals within 90 min of surgery. This hyperalgesia was not attenuated by postoperative injection of parecoxib. However, administration of tramadol completely prevented the development of postoperative hyperalgesia.
We have shown that the hyperalgesia in our model of postoperative pain is responsive to treatment with the analgesic tramadol, but it is not responsive to the selective COX-2 inhibitor parecoxib at the doses we used.
背景/目的：我们最近开发了一种新的术后疼痛动物模型，研究选择性环氧化酶-2（COX-2）抑制剂帕瑞昔布钠和镇痛药盐酸曲马多是否能减轻大鼠尾部小手术诱导的机械性原发性痛觉过敏。
手术时，大鼠用异氟烷麻醉，在其尾部皮肤和筋膜上做一个20毫米长的切口，然后缝合伤口。手术后立即给大鼠腹腔注射帕瑞昔布钠（10或20毫克/千克）、盐酸曲马多（10毫克/千克）或无菌生理盐水（0.1毫升/千克）。通过测量大鼠对施加于其尾部的钝性有害机械刺激（4牛）的反应潜伏期来评估痛觉过敏。在手术前和手术后90分钟进行伤害性测试。
所有注射生理盐水的动物在手术后90分钟内均出现痛觉过敏。术后注射帕瑞昔布并未减轻这种痛觉过敏。然而，给予曲马多可完全预防术后痛觉过敏的发生。
我们已经表明，我们的术后疼痛模型中的痛觉过敏对镇痛药曲马多治疗有反应，但对我们使用的剂量的选择性COX-2抑制剂帕瑞昔布无反应。
