Objective: To explore the distribution of retrograde FG-labeled neurons in the Mo5 (trigeminal motor nucleus) and Me5 (mesencephalic trigeminal nucleus) after FG injections into the masticatory muscles of mice. Methods: 8-12-week-old C57BL / 6 mice were divided into 6 groups(n=6). Each group was injected with Fluorogold (FG) into their zygomaticus, temporalis, masseter, anterior digastric, medial pterygoid and sternocleidomastoid muscles separately (sternocleidomastoid muscle as the control muscle). The expression of the trigeminal nuclei in mice was observed by fluorescence staining, and the expression and spatial distribution of FG-labeled neurons about different masticatory muscles were observed under microscope. Results: The labeled-neurons of masseter, temporalis and zygomaticus were found in Me5 and Mo5, the labeled neurons of medial pterygoid and anterior digastric were found in Mo5, and non labeled-neurons were found in sternocleidomastoid. Conclusion: It doesn’t exist a distinguished spatial distribution of the jaw-opening muscles and jaw-closing muscles in Mo5.  Me5 isn’t related to all the jaw-closing muscles.

目的：研究三叉神经运动核团（trigeminal motor nucleus,Mo5）和三叉神经中脑核团（mesencephalic trigeminal nucleus, Me5）对小鼠不同咀嚼肌的调控分布。方法：将8~12周龄C57BL/6小鼠分6组，每组3只，分别注射逆行性荧光示踪剂（Fluorogold，FG）到其颧肌、颞肌、咬肌、二腹肌前腹、翼内肌中，并以胸锁乳突肌作为对照组。通过荧光染色，显微镜下观察小鼠的三叉神经相关核团对于调控不同咀嚼肌群的表达及空间分布。结果：咬肌、颞肌和颧肌标记的初级运动神经元细胞出现在Me5和Mo5，翼内肌和二腹肌前腹标记只出现在Mo5，胸锁乳突肌注射后，在Me5和Mo5中均无标记神经元。结论：Mo5并没有关于升降颌肌群严格的空间分布，Me5并没有标记全部升颌肌群。