Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan.
Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan.
Arch Oral Biol. 2015 Mar;60(3):432-8. doi: 10.1016/j.archoralbio.2014.12.002. Epub 2014 Dec 11.
The purpose of this study was to investigate the functional role of bilateral hypoglossal (XII) nerve innervation of the tongue.
The possibility of bilateral innervation of XII nerve in the tongue was examined using postmortem fibre tracing in normal neonatal rats. In addition, immunohistochemical testing for synaptophysin or vesicular acetylcholine transporter (VAChT) was carried out in unilaterally XII nerve-resected neonatal rats.
Postmortem fibre tracing revealed constant distribution of the nerve fibres extending across the midline and existence of bilateral innervated area in the rostroventral and caudodorsal regions of the tongue. Synaptophysin-positive and VAChT-positive nerve terminals were also distributed continuously from the XII nerve-intact to the nerve-resected side across the midline of the tongue. The contralaterally projecting VAChT-positive nerve terminals were more numerous in suckling P2 rats (6.6 ± 0.5/section) than those in non-suckling P2 rats (4.9 ± 0.3/section) 24 h after nerve resection. Furthermore, the contralaterally projecting VAChT-positive nerve terminals were more numerous in P7 rats with nerve resection on P1 (6.3 ± 0.2/section) than those in P7 rats with nerve resection on P6 (3.1 ± 0.8/section).
We concluded that neonatal rats have two specific tongue regions receiving bilateral XII innervation, which allowed suckling in unilaterally XII nerve-resected neonatal rats.
本研究旨在探讨舌下神经（XII）双侧支配舌的功能作用。
通过对正常新生大鼠进行死后纤维追踪，研究了 XII 神经舌双侧支配的可能性。此外，还对单侧 XII 神经切断的新生大鼠进行了突触素或囊泡乙酰胆碱转运体（VAChT）的免疫组织化学检测。
死后纤维追踪显示，神经纤维跨越中线分布均匀，并存在双侧支配的舌前腹侧和后背侧区域。突触素阳性和 VAChT 阳性神经末梢也从中线完整的 XII 神经侧到神经切断侧连续分布。在神经切断后 24 小时，接受神经支配的 P2 期幼鼠（6.6 ± 0.5/节）中，对侧投射的 VAChT 阳性神经末梢比非吸吮 P2 期幼鼠（4.9 ± 0.3/节）更多。此外，在 P1 日接受神经切断的 P7 期幼鼠中，对侧投射的 VAChT 阳性神经末梢（6.3 ± 0.2/节）比在 P6 日接受神经切断的 P7 期幼鼠（3.1 ± 0.8/节）更多。
我们得出结论，新生大鼠有两个特定的舌区接受双侧 XII 神经支配，这使得单侧 XII 神经切断的新生大鼠能够吸吮。
