Direct projections from the central amygdaloid nucleus to the mesencephalic trigeminal nucleus in rats
Direct projections from the central amygdaloid nucleus to the mesencephalic trigeminal nucleus in rats
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DOI：
10.1016/j.brainres.2011.05.026
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发表时间：
2011-07
期刊：
影响因子：
2.9
通讯作者：
M. Shirasu;Takeshi Takahashi;Toshiharu Yamamoto;K. Itoh;S. Sato;Hiroyuki Nakamura
中科院分区：
文献类型：
--
作者：
M. Shirasu;Takeshi Takahashi;Toshiharu Yamamoto;K. Itoh;S. Sato;Hiroyuki Nakamura
杏仁核被恐惧激活，在对危及生命的情况下的情绪反应中发挥着重要作用。当老鼠感到受到威胁时，它们会猛烈地咬人。咬合强度由三叉神经运动核和三叉神经中脑核团(Me5)调节。Me5将来自咀嚼肌和牙周韧带的本体感觉信号传递到三叉神经运动和运动前核团。杏仁核投射到三叉神经运动核和运动前网状结构。然而，杏仁核是否直接投射到Me5还不清楚。在本研究中，将逆行示踪剂Fast Blue注入Me5尾侧，标记杏仁中央核(ACEs)神经元，并向ACEs注入生物素化葡聚糖胺，观察ACEs至Me5的纤维和终末纽扣。此外，将与辣根过氧化物酶标记的小麦胚凝集素注入ACE，并对Me5的标记纤维和末端纽扣进行了电子显微镜观察。Me5胞体上的标记末端按钮在尾部比在吻部更丰富。电子显微镜观察发现，这些终末按钮中的一部分形成了轴体突触。这些结果表明，ACE向Me5发出直接投射，并提示杏仁核通过改变Me5中的神经元活动来调节咬合强度。
The amygdala is activated by fear and plays an important role in the emotional response to life-threatening situations. When rats feel threatened, they respond by biting fiercely. Bite strength is regulated by the trigeminal motor nucleus and the mesencephalic trigeminal nucleus (Me5). The Me5 relays proprioceptive signals from the masticatory muscles and the periodontal ligaments to the trigeminal motor and premotor nuclei. The amygdala projects to the trigeminal motor nucleus and the premotor reticular formation. However, it is unknown whether the amygdala projects directly to the Me5. In the present study, neurons of the central amygdaloid nucleus (ACe) were labeled following injection of a retrograde tracer, Fast Blue, into the caudal Me5, and fibers and terminal buttons from the ACe to the Me5 were examined after injections of an anterograde neuronal tracer, biotinylated dextran amine into the ACe. Furthermore, wheat germ agglutinin-conjugated to horseradish peroxidase was injected into the ACe, and labeled fibers and terminal buttons in the Me5 were examined by electron microscopy. Labeled terminal buttons on Me5 somata were more abundant in the caudal than the rostral Me5. Electron microscopic observation revealed that a part of these terminal buttons formed axo-somatic synapses. These results indicate that the ACe sends direct projections to the Me5, and suggest that the amygdala regulates bite strength by modifying neuronal activity in the Me5.