Periodontal Ligament as a sensory apparaus : A morphological approach to functional property of periodontal nerve terminals

1.非特异性胆碱酯酶与蛋白基因产物9.5(Pgp)双重染色显示，机械感受器主要分布于牙根尖附近区域，而伤害性感受器密集分布于牙周膜全长。在组织化学研究中，几乎所有Ruffini终末轴突中的线粒体都显示出强烈的非特异性胆碱酯酶。与牙周Ruffini末梢相关的终末Scwann细胞呈酸性磷酸酶阳性。应用免疫组织化学和免疫细胞化学方法研究Ruffini末端的发育和成熟过程，这些过程需要牙齿萌出和咬合力等功能刺激的补充。用免疫组织化学方法检测牙周神经对实验性咬合创伤大鼠磨牙的反应。在咬合抬高后的第二天，许多Ruffini末端肿胀，其轮廓在光…上不清楚更微观的层面。电子显微镜下，异常长的细胞质突起通过雪旺细胞覆盖层的扩大缝隙延伸，雪旺氏鞘的空洞数目减少。此外，第2~4天，牙周膜受压侧细神经纤维排列不规则，外观突出。珠状神经在抬高后2-4天出现增加，并随着时间的推移而减少。这些结果提示，腹膜损伤后牙周膜神经末梢的分布和形态发生了特殊的变化。为了阐明与颌骨反射有关的神经调节剂的种类，在咬肌内微量注射HRP，然后用免疫细胞化学方法检测猫三叉神经运动核内的5-羟色胺。HRP标记的运动神经元与5-羟色胺阳性神经纤维形成突触。本研究结果提示，5-羟色胺是控制颌骨运动的神经调节剂之一。较少

1. Double staining with non-specific cholinesterase and protein gene product 9.5 (PGP) clearly demonstrated that mechanoreceptors are restricted to the area near root apex while nociceptors are densely distributed throughout the whole length of periodontal ligament.2. In histochemical studies, almost all mitochondria in the axon terminals of Ruffini endings showed intense non-specific cholinesterase. Terminal Scwann cells associated with periodontal Ruffini endings were positive for acid phosphatase.3. The development and maturation process of Ruffini endings were investigated by use of immunohistocheistry and immunocytochemistry for PGP.These processed require the additions of functional stimuli such as tooth eruption and occlusal force.4. The responses of periodontal nerves to experimentally induced occlusal trauma in rat molars were assessed by immunohistochemistry for PGP.By the second day after bite-raising, many Ruffini endings were swollen and their outline were unclear at light … More microscopic level. Under electron microscope, unusual long cytoplasmic projections extended through enlarged slits of Schwann cell covering, and the cavcolac of the Schwann sheaths had decreased in number. Furthermore, from days 2 to 4, thin nerve fibers on the pressure side of the periodontal ligament were oriented irregulary and had a prominet beated appearance. An increase in the beaded nerves occurred in between days 2-4 post elevation, and decreased over the time course. These results suggest celusal trauma induces specific changes in the distribution and shape of nerve terminals in the periodontal ligament.5. For elucidation in the kinds of neuromodulater concerning jaw-reflexes, microinjection with HRP into masseter was done followed by immunocytochemistry for serotonin in cat trigeminal motor nucleus. The HRP-labelled motor neuron formed synapse with serotonin-positive nerve fibers. The results in this study suggest serotonin is one of neuromodulators for control of jaw-movement. Less