Spontaneous discharge and increased heat sensitivity of rat C-fiber nociceptors are present in vitro after plantar incision
Spontaneous discharge and increased heat sensitivity of rat C-fiber nociceptors are present in vitro after plantar incision
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DOI：
10.1016/j.pain.2004.08.026
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发表时间：
2004-11-01
期刊：
影响因子：
7.4
通讯作者：
Brennan, TJ
中科院分区：
文献类型：
--
作者：
Banik, RK;Brennan, TJ
术后疼痛的特征是手术部位的自发性疼痛和运动引起的疼痛增加。为了研究术后疼痛机制，我们研究了足底切口后1天大鼠无毛后爪皮肤的机械-热敏C纤维传入神经的放电特性。术后1天出现自发性疼痛、发热和机械性痛觉过敏。记录传入使用在体外无毛皮肤神经制备表明，更多的C-纤维从切口比对照组大鼠有自发放电。与无自发活动的纤维相比，切割大鼠自发放电纤维的热反应阈值较低。在距离切口小于2 mm的所有纤维中，对较低温度（35-41 ℃）有反应的百分比增加，平均热反应阈值低3.1 ℃，热诱发反应的刺激-反应函数向左移动，对33-48 ℃热刺激反应的脉冲总数增加。然而，距切口超过2 mm的C纤维的热反应与对照组没有差异。通过伺服力控制刺激器测量的平均机械反应阈值在组间没有差异。在阈上机械刺激诱发的总尖峰不增加从切口传入。总之，1天后，切口，当行为表明自发性疼痛，热和机械痛觉过敏存在，C-纤维接近切口显示自发放电和致敏热，但不机械刺激，在体外。(C)2004年国际疼痛研究协会。Elsevier B. V.出版，保留所有权利。
Postoperative pain is characterized by spontaneous pain at the surgical site and increased pain due to movements. To study postoperative pain mechanisms, we investigated discharge properties of mechano-heat sensitive C-fiber afferents innervating the rat glabrous hindpaw skin 1 day after plantar incision. Behaviors indicating spontaneous pain, heat and mechanical hyperalgesia were present 1 day after incision. Recording of afferents using in vitro glabrous skin-nerve preparation showed that more C-fibers from the incision had spontaneous discharge than control rats. The spontaneously discharging fibers from incised rats had lower heat response threshold compared with fibers without spontaneous activity. In all fibers less than 2 mm from the incision, an increased percentage responded to lower temperatures (35-41 degreesC), the mean heat response threshold was 3.1 degreesC less, the stimulus-response function for heat evoked response was shifted to the left and the total number of impulses in response to a 33-48 degreesC heat stimulus was increased. Heat responses of C-fibers more than 2 mm from the incision, however, were not different from control. The mean mechanical response thresholds, measured by a servo force-controlled stimulator, were not different between groups. The total spikes evoked at supra-threshold mechanical stimulation were not increased in afferents from the incision. In conclusion, 1 day after incision, when behaviors indicating spontaneous pain, heat and mechanical hyperalgesia are present, C-fibers close to incision showed spontaneous discharge and sensitization to heat but not to mechanical stimuli, in vitro. (C) 2004 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.