Morphological approach to the clucidation of recognition of recognition mechanism of periodontal sensation: Immunohistochemical and electron microscopic study.

为了阐明牙周感觉感受器的生物学特性，采用免疫组织化学、组织化学和透射电镜技术对大鼠牙周膜Ruffini末梢进行了研究。牙周Ruffini终末的超微结构特征为轴突终末扩张，充满大量线粒体，外覆一层厚的雪旺氏鞘，鞘上有多层无定形物质。雪旺氏鞘覆盖是不连续的，因此轴质的指状突起，即轴突棘，通过雪旺氏鞘的狭缝暴露于周围组织。鞣酸染色标本电镜观察显示轴索棘与周围牙周膜胶原纤维不直接接触.通过层粘连蛋白抗体的免疫染色，Ruffini终末轴突末端周围的无定形结构被清楚地确定为基底层。由于已知层粘连蛋白参与细胞粘附，因此多层基底层将充当牙周纤维与Ruffini末梢的轴突末端之间的粘附结构。这将解释牙周感觉高度敏感的原因。组织化学染色显示牙周Ruffini终末细胞色素氧化酶和酸性磷酸酶活性以及非特异性胆碱酯酶活性.牙周Ruffini终末的成熟似乎需要功能性刺激，如牙齿皱缩和咬合.在实验性牙齿移动过程中，牙周神经的分布由于机械力的作用而发生剧烈的变化.在骨整合组织中，未观察到种植体材料周围形成识别机制。

In order to clarify the biological property of periodontal sensory receptors, Ruffini endings in the periodontal ligament of rats were examincd by immunohistochemistry, histochemistry and transmission electron microscopy, whereby it resulted that:1. The periodontal Ruffini endings were ultrastructurally characterized by the expanded axon terminals filled with a large number of mitochondria and covered with a thick Schwann sheath, over which a the multiple layer of amorphous substances was observed. The Schwann sheath covering was discontinuous, so that the finger-like projections of the axoplasm,i.e. axonal spines, were exposed to the surrounding tissues through the slits of the Schwann sheath. Electron microscopic observation of specimens stained with tannic acid revealed that the axonal spines were not in direct contact with the surrounding periodontal collage fibers.2. By immunostaining with antibody to laminin, the amorphous structure around the axon terminals of Ruffini endings was clearly identified as the basal lamina. Since laminin is known to be involved in cell adhesion, the multiple-layered basal lamina would serve as an adhesive structure between the periodontal fibers and the axon terminals of Ruffini endings. This would bring an explanation as to the reason by which periodontal sensation is highly sensitive.3. Histochemical stainings disclosed intense cytochrome oxidase and acid phosphatase activities as well as nonspecific cholinesterase activity in periodontal Ruffini endings.4. The maturation of the periodontal Ruffini endings seemed to require functional stimuli such as tooth cruption and occlusion.5. During experimental tooth movement, the distribution of periodontal nerves drastically changed due to mechanical force.6. In osseointegrated tissues, no formation of recognition mechanism was observed around implant materials.