Takeuchi Y, Chen X H, Fukui Y, Itoh M, Miki T, Miyoshi S
Department of Anatomy, Kagawa Medical School, Japan.
Brain Res Bull. 1993;31(1-2):57-65. doi: 10.1016/0361-9230(93)90011-y.
Iontophoretic injection of horseradish peroxidase (HRP) into the medial part of the facial nucleus resulted in retrograde labeling in the lateral midbrain tegmentum contralaterally which corresponded to the paralemniscal zone (PL). Further experiments in which HRP was injected iontophoretically into the PL revealed heavy retrograde labeling in the lateral portion of the ipsilateral periaqueductal gray (PAG). These light microscopic studies indicated the possibility of the pathway from the PAG to the facial nucleus via the midbrain PL. The electron microscopic observations were carried out on the lateral midbrain tegmentum containing the PL after kainic acid, and wheat germ agglutinin conjugated HRP injections were made into the PAG and the contralateral facial nucleus in the same animal, respectively. Although in the neuropil many degenerating PAG fibers and retrogradely labeled neurons were observed, it was of particular interest that the degenerating fibers made synaptic contacts with HRP-labeled somata and dendrites.
将辣根过氧化物酶（HRP）离子导入面神经核内侧部分，导致对侧中脑外侧被盖区出现逆行标记，该区域对应于旁臂旁区（PL）。进一步的实验中，将HRP离子导入PL，结果显示同侧导水管周围灰质（PAG）外侧部分出现大量逆行标记。这些光学显微镜研究表明，存在从PAG经中脑PL至面神经核的通路的可能性。在用海藻酸处理后，对含有PL的中脑外侧被盖区进行了电子显微镜观察，并在同一只动物中分别将小麦胚芽凝集素结合的HRP注入PAG和对侧面神经核。虽然在神经毡中观察到许多变性的PAG纤维和逆行标记的神经元，但特别有趣的是，变性纤维与HRP标记的胞体和树突形成了突触联系。
