Kido Mizuho A, Ibuki Teiichi, Danjo Atsushi, Kondo Teruyoshi, Zhang Jing-Qi, Yamaza Takayoshi, Yamashita Yoshio, Higuchi Yoshinori, Tanaka Teruo
Department of Oral Anatomy and Cell Biology, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan.
Arch Histol Cytol. 2005 Dec;68(4):259-65. doi: 10.1679/aohc.68.259.
The dentin-pulp complex is a peripheral end-organ supplied by dense sensory nerve fibers. Substance P, a representative neuropeptide widely distributed in the dental pulp, has been reported to play roles in pain transmission and the amplification of inflammation. We analyzed here the expression of the neurokinin 1 (NK1) receptor, preferentially activated by substance P, using immunocytochemistry in rat dental pulp at both the light and electron microscopic levels. Conspicuous NK1 receptor immunoreactivity was found in the odontoblasts; immunolabelings were present at their plasma membrane and endosomal structures, especially in their cytoplasmic processes. Immunoreactions for NK1 receptor were also detectable in a part of the nerve terminals associated with the cytoplasmic processes of the odontoblasts. Furthermore, the endothelial cells of capillaries and post-capillary venules and the fibroblasts were labeled with the NK1 receptor in the subodontoblast layer. These findings suggest that pulpal cells and nerve fibers are targets for substance P that mediate multiple functions, including a vasoactive function and the regulation of vascular permeability as well as the modulation of pain transmission.
牙髓复合体是一个由密集的感觉神经纤维供应的外周终末器官。P物质是一种广泛分布于牙髓中的代表性神经肽，据报道它在疼痛传递和炎症放大中起作用。我们在此利用免疫细胞化学技术，在光镜和电镜水平上分析了牙髓中优先被P物质激活的神经激肽1（NK1）受体的表达。在成牙本质细胞中发现了明显的NK1受体免疫反应性；免疫标记出现在它们的质膜和内体结构上，尤其是在它们的细胞质突起中。在与成牙本质细胞的细胞质突起相关的部分神经末梢中也可检测到NK1受体的免疫反应。此外，在成牙本质细胞下层的毛细血管和毛细血管后微静脉的内皮细胞以及成纤维细胞也被NK1受体标记。这些发现表明，牙髓细胞和神经纤维是P物质的作用靶点，P物质介导多种功能，包括血管活性功能、血管通透性调节以及疼痛传递的调节。
