Nam T S, Yeon D S, Leem J W, Paik K S
Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
Yonsei Med J. 2000 Apr;41(2):252-7. doi: 10.3349/ymj.2000.41.2.252.
We investigated the adrenergic sensitivity of afferent fibers in the L4 dorsal roots of rats with a unilateral ligation of the L5-L6 spinal nerves. About 12% of nociceptive fibers on the affected side were excited by sympathetic stimulation or by intra-arterial injection of norepinephrine which did not affect A beta-fiber activity. Sympathetic excitation of nociceptive fibers was suppressed by alpha 1-antagonist prazosin, while it was unaffected by alpha 2-antagonist yohimbine. Most of these fibers were excited by intra-arterial injection of alpha 1-agonist phenylephrine, without being affected by an injection of alpha 2-agonist clonidine. Sympathetic excitation was blocked by lidocaine applied near the receptive fields of recorded fibers. The results suggested that some nociceptors remaining intact after partial nerve injury become sensitive to sympathetic activity by the mediation of alpha 1-adrenoceptors in the peripheral endings.
我们通过单侧结扎大鼠L5-L6脊神经，研究了L4背根传入纤维的肾上腺素能敏感性。在患侧，约12%的伤害性纤维可被交感神经刺激或动脉内注射去甲肾上腺素兴奋，而这并不影响Aβ纤维的活动。伤害性纤维的交感神经兴奋可被α1拮抗剂哌唑嗪抑制，而不受α2拮抗剂育亨宾的影响。这些纤维中的大多数可被动脉内注射α1激动剂去氧肾上腺素兴奋，而不受α2激动剂可乐定注射的影响。交感神经兴奋可被应用于记录纤维感受野附近的利多卡因阻断。结果表明，部分神经损伤后仍保持完整的一些伤害感受器通过外周末梢α1肾上腺素能受体的介导，对交感神经活动变得敏感。
