Gold M S, White D M, Ahlgren S C, Guo M, Levine J D
Department of Medicine, University of California, San Francisco 94143-0452.
Neurosci Lett. 1994 Jul 4;175(1-2):166-70. doi: 10.1016/0304-3940(94)91105-3.
C-Fiber mechanoheat (C-MH) nociceptors from the saphenous nerve were studied, in control rats and in rats that underwent surgical sympathectomy. Intradermal injection, alone, of either norepinephrine (NE) or the calcium ionophore, A23187, did not affect mechanical threshold. The combination of A23187 and NE, however, significantly decreased mechanical threshold. In the presence of the alpha 2-adrenergic antagonist, yohimbine, or the cyclooxygenase inhibitor, indomethacin, C-MHs were not sensitized by the combination of NE + A23187. One week after surgical sympathectomy, the number of C-MHs sensitized by NE + A23187 was significantly reduced. In summary, NE appears to sensitize nociceptors indirectly. These data are compatible with the suggestion that a sympathetic postganglionic neuron-dependent release of prostaglandins mediates the sensitization. NE appears to act at an alpha 2-adrenergic receptor, only in the presence of an increased intracellular Ca2+.
对来自隐神经的C类纤维机械热（C-MH）伤害感受器进行了研究，研究对象包括对照大鼠和接受手术交感神经切除术的大鼠。单独皮内注射去甲肾上腺素（NE）或钙离子载体A23187，均不影响机械阈值。然而，A23187与NE联合使用时，会显著降低机械阈值。在存在α2-肾上腺素能拮抗剂育亨宾或环氧化酶抑制剂吲哚美辛的情况下，NE + A23187联合使用不会使C-MH感受器致敏。手术交感神经切除术后一周，被NE + A23187致敏的C-MH感受器数量显著减少。总之，NE似乎间接使伤害感受器致敏。这些数据与以下观点一致：交感神经节后神经元依赖性前列腺素释放介导了这种致敏作用。NE似乎仅在细胞内Ca2+增加的情况下作用于α2-肾上腺素能受体。
