Yamashiro T, Satoh K, Nakagawa K, Moriyama H, Yagi T, Takada K
Department of Orthodontics, Okayama University Dental School, Japan.
J Dent Res. 1998 Nov;77(11):1920-5. doi: 10.1177/00220345980770110901.
Orthodontic tooth movement is known to cause pain and discomfort to patients. Mechanically induced inflammatory responses in the periodontium are assumed to be related to the mechanism of pain sensation. An immediate-early gene, c-fos, that is expressed within some neurons following synaptic activation, is widely used as a marker for neuronal activity following noxious or innocuous stimulation. We have recently demonstrated that experimental tooth movement produced Fos induction in the ipsilateral trigeminal subnucleus caudalis and in the bilateral lateral parabrachial nucleus, which is known to be involved in the transmission of nociceptive information. As a further step, we investigated the distribution of Fos-like immunoreactive neurons in the upper brain regions. Twenty-four hours after the commencement of the experimental tooth movement, the Fos-like immunoreactive neurons appeared in the central nucleus of the amygdala (Ce), paraventricular nucleus of the hypothalamus (PVH), and paraventricular nucleus of the thalamus (PV) of the experimental rats. The numbers of the labeled neurons were significantly increased by 639% (P < 0.001) and 644% (P < 0.001) in the ipsilateral and contralateral sides of the Ce, respectively, by 292% (P < 0.001) and 307% (P < 0.001) in the ipsilateral and contralateral sides of the PVH, and by 264% (P < 0.0001) in the PV with respect to sham control rats. These results suggest that nociceptive information caused by experimental tooth movement might be transmitted and modulated in several regions of the forebrain.
正畸牙齿移动会给患者带来疼痛和不适。牙周组织中机械诱导的炎症反应被认为与疼痛感觉机制有关。一种即刻早期基因c-fos，在突触激活后会在某些神经元中表达，被广泛用作有害或无害刺激后神经元活动的标志物。我们最近证明，实验性牙齿移动在同侧三叉神经尾侧亚核和双侧外侧臂旁核中诱导了Fos表达，而外侧臂旁核已知参与伤害性信息的传递。作为进一步的研究，我们调查了Fos样免疫反应性神经元在上脑区的分布。实验性牙齿移动开始24小时后，Fos样免疫反应性神经元出现在实验大鼠的杏仁核中央核（Ce）、下丘脑室旁核（PVH）和丘脑室旁核（PV）中。与假手术对照组大鼠相比，Ce同侧和对侧标记神经元的数量分别显著增加了639%（P < 0.001）和644%（P < 0.001），PVH同侧和对侧分别增加了292%（P < 0.001）和307%（P < 0.001），PV中的标记神经元数量增加了264%（P < 0.0001）。这些结果表明，实验性牙齿移动引起的伤害性信息可能在前脑的几个区域进行传递和调节。
