Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, South Korea.
Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, South Korea.
Neuromodulation. 2020 Feb;23(2):167-176. doi: 10.1111/ner.13059. Epub 2019 Nov 5.
The role of the nucleus accumbens (NAc) in chronic neuropathic pain has been suggested, but the role of the NAc in dorsal root ganglion (DRG) neuropathic pain remains unclear. The objective of this study was to determine whether optogenetic stimulation of the NAc influences DRG compression-induced neuropathic pain.
We established sham or DRG lesions in female Sprague-Dawley rats by L4-5 DRG root compression, and the animals received unilateral injections of optogenetic virus in the NAc core. We employed reflexive pain tests to assess the alterations between the groups at the light on/off states. To determine thalamic firing, we performed single-unit in vivo extracellular recording. For statistical analysis, we used one- or two-way repeated-measures analysis of variance.
Compared to sham-operated rats, chronic compressed DRG rats showed elevated behavioral sensitivity and sustained neuronal hyperexcitability in the thalamus. NAc optic stimulation improved pain behaviors and lowered thalamic discharge from ventral posterolateral thalamic nuclei.
The NAc core impacts the reward and motivational aspects of chronic neuropathic pain influenced by limbic behaviors to thalamic discharge. Increased thalamic firing activity may result in chronic compressed DRG-induced neuropathic pain, and optogenetic neuromodulation of the NAc can ease chronic pain and thalamic discharge.
已有人提出伏隔核（NAc）在慢性神经性疼痛中的作用，但 NAc 在背根神经节（DRG）神经性疼痛中的作用尚不清楚。本研究旨在确定 NAc 的光遗传学刺激是否会影响 DRG 压迫引起的神经性疼痛。
我们通过 L4-5 DRG 神经根压迫在雌性 Sprague-Dawley 大鼠中建立假手术或 DRG 损伤模型，并在 NAc 核心中单侧注射光遗传学病毒。我们采用反射性疼痛测试来评估各组在光开启/关闭状态下的变化。为了确定丘脑放电，我们进行了单细胞在体细胞外记录。对于统计分析，我们使用单向或双向重复测量方差分析。
与假手术大鼠相比，慢性压缩 DRG 大鼠表现出行为敏感性升高和丘脑神经元过度兴奋。NAc 光刺激可改善疼痛行为并降低腹后外侧核的丘脑放电。
NAc 核心影响由边缘行为引起的慢性神经性疼痛的奖赏和动机方面，从而影响到丘脑放电。增加的丘脑放电活动可能导致慢性压缩 DRG 引起的神经性疼痛，而 NAc 的光遗传学神经调节可以缓解慢性疼痛和丘脑放电。
