Involvement of spinal 2-adrenoceptors in prolonged modulation of hind limb withdrawal reflexes following acute noxious stimulation in the anaesthetized rabbit
Involvement of spinal 2-adrenoceptors in prolonged modulation of hind limb withdrawal reflexes following acute noxious stimulation in the anaesthetized rabbit
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DOI：
10.1111/ejn.13185
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发表时间：
2016-03-01
影响因子：
3.4
通讯作者：
Harris, John
中科院分区：
文献类型：
--
作者：
Harris, John
在戊巴比妥麻醉的家兔中，研究了脊髓（2）-肾上腺素能受体在远距离异位和局部异位位置急性有害化学刺激后，在介导后肢撤回反射的长期调节中的作用。电刺激同侧足跟引起的踝伸肌内侧腓肠肌反射，以及刺激同侧足趾根部引起的踝胫前屈肌和膝屈肌半腱肌反射，在鼻端或对侧腓肠肌内涂抹芥子油（20%）后可抑制1 h以上。脚跟MG反应也被抑制后，应用芥子油跨足底跖趾关节的同侧脚，而这种同伦刺激促进屈肌反应。芥末油也引起了显着的升压作用时，适用于任何三个测试网站。选择性β-肾上腺素能受体拮抗剂RX 821002（100- 300 g，鞘内注射）对反射本身无影响，但可引起平均动脉血压降低。在（2）-阻断剂的存在下，芥子油对反射的抑制和易化作用被完全消除。这些数据表明，脊髓反射的长期持久抑制急性伤害性刺激后，遥远的位置涉及脊髓上的去甲肾上腺素能通路的激活，其影响是依赖于一个完整的（2）-肾上腺素受体系统在脊髓水平。这些通路和受体似乎也参与了对同一肢体施加伤害性刺激后的反射促进（敏化）和抑制。
The role of spinal (2)-adrenoceptors in mediating long-lasting modulation of hind limb withdrawal reflexes following acute noxious chemical stimulation of distant heterotopic and local homotopic locations has been investigated in pentobarbitone-anaesthetized rabbits. Reflexes evoked in the ankle extensor muscle medial gastrocnemius (MG) by electrical stimulation of the ipsilateral heel, and reflexes elicited in the ankle flexor tibialis anterior and the knee flexor semitendinosus by stimulation at the base of the ipsilateral toes, could be inhibited for over 1h after mustard oil (20%) was applied to either the snout or into the contralateral MG. The heel-MG response was also inhibited after applying mustard oil across the plantar metatarsophalangeal joints of the ipsilateral foot, whereas this homotopic stimulus facilitated both flexor responses. Mustard oil also caused a significant pressor effect when applied to any of the three test sites. The selective (2)-adrenoceptor antagonist, RX 821002 (100-300g, intrathecally), had no effect on reflexes per se, but did cause a decrease in mean arterial blood pressure. In the presence of the (2)-blocker, inhibitory and facilitatory effects of mustard oil on reflexes were completely abolished. These data imply that long-lasting inhibition of spinal reflexes following acute noxious stimulation of distant locations involves activation of supraspinal noradrenergic pathways, the effects of which are dependent on an intact (2)-adrenoceptor system at the spinal level. These pathways and receptors also appear to be involved in facilitation (sensitization) as well as inhibition of reflexes following a noxious stimulus applied to the same limb.