Long-term sensitization of primary afferents in adult rats exposed to neonatal colon pain
Long-term sensitization of primary afferents in adult rats exposed to neonatal colon pain
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DOI：
10.1016/s0006-8993(03)02358-8
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发表时间：
2003-05-02
期刊：
影响因子：
2.9
通讯作者：
Al-Chaer, ED
中科院分区：
文献类型：
--
作者：
Lin, C;Al-Chaer, ED
我们之前已经表明，新生儿的结肠刺激（CI）会导致成年大鼠的慢性内脏过敏，在没有可识别的外周病理的情况下与中枢神经元敏化相关。本研究的目的是通过检查胸腰段（TL）和腰骶段（LS）脊柱节段的初级传入神经对分级结直肠扩张（CRD）的反应变化，评估外周机制对慢性内脏过敏的相对贡献。在成年对照和 CI 大鼠的脊髓背根 (DR) 的切割远端记录传入放电。我们发现：（1）Cl 大鼠 LS 传入神经激活的平均阈值显着降低； (2)Cl大鼠TL和LS传入神经对CRD的反应显着高于对照组; (3)Cl组大鼠LS传入神经的自发活动明显强于对照组; (4)在Cl大鼠中，LS DR对分级CRD的平均反应显着高于TL DR； (5)C1大鼠中CRD激活的LS DR和TL DR的数量均显着多于对照组。总之，结果表明，慢性内脏过敏与外周敏化以及中枢敏化相关。与急性伤害性输入相比，TL 内脏传入神经投射似乎更多地参与来自结肠的敏感伤害性输入的处理。然而，LS 传入神经似乎在敏化和急性疼痛状态下同样重要。 (C) 2003 Elsevier Science B.V. 保留所有权利。
We have previously shown that colon irritation (CI) in neonates results in chronic visceral hypersensitivity in adult rats, associated with central neuronal sensitization in the absence of identifiable peripheral pathology. The purpose of this study is to assess the relative contribution of peripheral mechanisms to chronic visceral hypersensitivity by examining the changes in responses of primary afferents at thoracolumbar (TL) and lumbosacral (LS) spinal segments to graded colorectal distension (CRD). Afferent discharges were recorded at the cut distal ends of spinal dorsal roots (DRs) in adult control and CI rats. We found that: (1) the average threshold of activation of LS afferents decreased significantly in Cl rats; (2) the responses of TL and LS afferents to CRD in Cl rats were significantly greater than those in control; (3) the spontaneous activity of LS afferents in Cl rats was significantly stronger than that in control; (4) in Cl rats, the average responses to graded CRD of LS DRs were significantly higher than those of TL DRs; and (5) the number of both LS DRs and TL DRs activated by CRD in Cl rats was significantly larger than control. In summary, the results show that chronic visceral hypersensitivity is associated with peripheral sensitization, as well as central sensitization. TL visceral afferents projecting seem to be more involved in the processing of sensitized nociceptive input from the colon than acute nociceptive input. However, LS afferents seem to be equally important in both sensitized and acute pain states. (C) 2003 Elsevier Science B.V. All rights reserved.