Liu Qing-Ying, Chen Wen, Cui Shuang, Liao Fei-Fei, Yi Ming, Liu Feng-Yu, Wan You
Neuroscience Research Institute, Peking University, Beijing 100083, China; Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing 100083, China; Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing 100083, China.
Neuroscience Research Institute, Peking University, Beijing 100083, China.
Neurosci Res. 2019 May;142:30-37. doi: 10.1016/j.neures.2018.04.002. Epub 2018 Apr 21.
Besides the injured peripheral dorsal root ganglion (DRG) neurons, the adjacent intact DRG neurons also have important roles in neuropathic pain. Ion channels including Ca3.2 T-type calcium channel in the DRG neurons are important in the development of neuropathic pain. In the present study, we aimed to examine the expression of Ca3.2 T-type calcium channels in the intact DRG neurons in neuropathic pain. A neuropathic pain model of rat with lumbar 5 (L5) spinal nerve ligation (SNL) was established, in which the L4 DRG was separated from the axotomized L5 DRG, and the molecular, morphological and electrophysiological changes of Ca3.2 T-type calcium channels in L4 DRG neurons were investigated. Western blotting showed that total and membrane protein levels of Ca3.2 in L4 DRG neurons increased, and voltage-dependent patch clamp recordings revealed an increased T-type current density with a curve shift to the left in steady-state activation in the acutely isolated L4 DRG neurons in neuropathic pain rats. Immunofluorescent staining further showed that the membrane expression of Ca3.2 increased in CGRP-, IB4-positive small neurons and NF200-positive large ones. In conclusion, the membrane expression and the function of Ca3.2 T-type calcium channels are increased in the intact L4 DRG neurons in neuropathic pain rats with peripheral nerve injury like SNL.
除了受损的外周背根神经节（DRG）神经元外，相邻的完整DRG神经元在神经性疼痛中也发挥着重要作用。DRG神经元中的离子通道，包括Ca3.2 T型钙通道，在神经性疼痛的发展中起着重要作用。在本研究中，我们旨在检测神经性疼痛状态下完整DRG神经元中Ca3.2 T型钙通道的表达。建立了大鼠腰5（L5）脊神经结扎（SNL）所致的神经性疼痛模型，将L4 DRG与切断轴突的L5 DRG分离，研究L4 DRG神经元中Ca3.2 T型钙通道的分子、形态和电生理变化。蛋白质免疫印迹法显示，L4 DRG神经元中Ca3.2的总蛋白水平和膜蛋白水平均升高，电压依赖性膜片钳记录显示，在神经性疼痛大鼠急性分离的L4 DRG神经元中，T型电流密度增加，稳态激活曲线向左移位。免疫荧光染色进一步显示，Ca3.2在降钙素基因相关肽（CGRP）、IB4阳性的小神经元和神经丝蛋白200（NF200）阳性的大神经元中的膜表达增加。总之，在患有如SNL这种外周神经损伤的神经性疼痛大鼠中，完整的L4 DRG神经元中Ca3.
