Hypoglossal nucleus projections to the rat masseter muscle

详细信息    查看全文

• 作者：O. Mameli ; S. Stanzani ; A. Russo ; R. Pellitteri ; M. Spatuzza ; M.A. Caria ; G. Mulliri ; P.L. De Riu
• 关键词：Rat ; Mystacial pad extrinsic muscle ; Masseter muscle spindle ; Hypoglossal neuron
• 刊名：Brain Research
• 出版年：2009
• 出版时间：4 August 2009
• 年：2009
• 卷：1283
• 期：Complete
• 页码：34-40
• 全文大小：3181 K

文摘

We investigated in the rat whether hypoglossal innervation extended to facial muscles other than the extrinsic musculature of the mystacial pad. Results showed that hypoglossal neurons also innervate the masseter muscle. Dil injected into the XII nucleus showed hypoglossal axons in the ipsilateral main trunk of the trigeminal nerve. After Gasser's ganglion crossing, the axons entered into the infraorbital division of the trigeminal nerve and targeted the extrinsic muscles of the mystacial pad. They also spread into the masseter branch of the trigeminal nerve to target the polar portions of the masseter muscle spindles. Retrograde double labelling, performed by injecting Dil into the pad and True Blue into the ipsilateral masseter muscle, showed labelled hypoglossal neurons in the medio-dorsal portion of the XII nucleus. The majority of these neurons were small (15–20 μm diameter), showed fluorescence for Dil and projected to the mystacial pad. Other medium-size neurons (25 μm diameter) were instead labelled with True Blue and projected to the masseter muscle. Finally, in the same area, other small hypoglossal neurons showed double labelling and projected to both structures. Functional hypotheses on the role of these hypoglossal projections have been discussed.