Seo Kenji, Fujiwara Naoshi, Takeuchi Kiichi, Maeda Takeyasu, Someya Genji
Division of Dental Anesthesiology, Department of Tissue Regeneration and Reconstruction, Niigata University School of Health Sciences, 2-746, Asahimachi, Niigata, 951-9518, Japan.
Neuroreport. 2003 Jul 18;14(10):1321-5. doi: 10.1097/01.wnr.0000078544.07662.cc.
A high-speed optical imaging technique was employed for visualizing neuronal excitation propagation elicited by afferent stimulation in the mouse trigeminal caudalis (Vc) to clarify the central nociceptive modulation mechanism. Membrane depolarization evoked by a single-pulse stimulation to the spinal trigeminal tract (Tr) was propagated rostrally to the Vc, which was suppressed by CNQX. This is consistent with our morphological observation that axons expand from the Tr into the Vc. A trained-pulse (tetanus) stimulation to the Tr evoked a broad, persistent excitation in the Vc, while MK-801 suppressed it. Neonatally capsaicin-treated mice maintained a single-pulse response but a lacked tetanus-evoked one. These indicated that prolonged depolarization elicited by repetitive stimulation is a prerequisite to C-fiber excitation for activating the NMDA receptors.
采用高速光学成像技术来可视化小鼠三叉神经尾侧核（Vc）中由传入刺激引发的神经元兴奋传播，以阐明中枢伤害性感受调制机制。对脊髓三叉神经束（Tr）进行单脉冲刺激所诱发的膜去极化向头端传播至Vc，而这种传播被CNQX所抑制。这与我们的形态学观察结果一致，即轴突从Tr延伸至Vc。对Tr进行串刺激（强直刺激）可在Vc中诱发广泛、持续的兴奋，而MK-801可抑制这种兴奋。新生期用辣椒素处理的小鼠保持单脉冲反应，但缺乏串刺激诱发的反应。这些结果表明，重复性刺激所诱发的长时间去极化是激活NMDA受体从而使C纤维兴奋的先决条件。
