Direct projection from the lateral habenula to the trigeminal mesencephalic nucleus in rats
Direct projection from the lateral habenula to the trigeminal mesencephalic nucleus in rats
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DOI：
10.1016/j.brainres.2015.11.012
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发表时间：
2016-01
期刊：
影响因子：
2.9
通讯作者：
Haruka Ohara;Y. Tachibana;T. Fujio;Rieko Takeda-Ikeda;F. Sato;A. Oka;Takafumi Kato;Etsuko Ikenoue;T. Yamashiro;A. Yoshida
中科院分区：
文献类型：
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作者：
Haruka Ohara;Y. Tachibana;T. Fujio;Rieko Takeda-Ikeda;F. Sato;A. Oka;Takafumi Kato;Etsuko Ikenoue;T. Yamashiro;A. Yoshida
三叉神经中脑核（Vmes）神经元是传递咀嚼肌纺锤波或牙周机械感受器深层感觉的初级传入神经，对控制颌骨运动至关重要。它们的细胞体存在于大脑中，并接受与边缘（情绪）系统有关的各种皮层和皮层下结构的下行命令。然而，作为负面情绪（如疼痛、压力和焦虑）的中心，侧habenula （LHb）如何影响下颌运动的控制尚不清楚。为了解决这个问题，我们研究了LHb是否以及如何通过大鼠的神经束追踪技术直接投射到Vmes。在吻侧和尾侧vme注射逆行示踪剂氟金后，双侧LHb侧分裂（LHbl）中有大量神经元被标记，而双侧LHb内侧分裂（LHbm）中有少量神经元被标记。在LHbl注射顺行示踪剂生物素化右旋胺（BDA）后，在Vmes的吻侧和尾侧水平两侧分布少量标记轴突，其中一些标记轴突扣与Vmes神经元的吻侧和尾侧水平的细胞体双侧接触。然而，BDA注射到LHbm后，Vmes的吻侧和尾侧水平没有双侧轴突被标记。因此，本研究首次展示了下颚神经向下颌神经的直接投射和详细的投射模式，表明下颚运动是由下颚神经发出的负面情绪信号所调节的。
Trigeminal mesencephalic nucleus (Vmes) neurons are primary afferents conveying deep sensation from the masticatory muscle spindles or the periodontal mechanoreceptors, and are crucial for controlling jaw movements. Their cell bodies exist in the brain and receive descending commands from a variety of cortical and subcortical structures involved in limbic (emotional) systems. However, it remains unclear how the lateral habenula (LHb), a center of negative emotions (e.g., pain, stress and anxiety), can influence the control of jaw movements. To address this issue, we examined whether and how the LHb directly projects to the Vmes by means of neuronal tract tracing techniques in rats. After injections of a retrograde tracer Fluorogold in the rostral and caudal Vmes, a number of neurons were labeled in the lateral division of LHb (LHbl) bilaterally, whereas a few neurons were labeled in the medial division of LHb (LHbm) bilaterally. After injections of an anterograde tracer, biotinylated dextranamine (BDA) in the LHbl, a small number of labeled axons were distributed bilaterally in the rostral and caudal levels of Vmes, where some labeled axonal boutons contacted the cell body of rostral and caudal levels of Vmes neurons bilaterally. After the BDA injection into the LHbm, however, no axons were labeled bilaterally in the rostral and caudal levels of Vmes. Therefore, the present study for the first time demonstrated the direct projection from the LHbl to the Vmes and the detailed projection patterns, suggesting that jaw movements are modulated by negative emotions that are signaled by LHbl neurons.