The basic study for the maintenance of oral health in an aging society

本项目旨在阐明黑质纹状体多巴胺能通路在咀嚼过程中的作用。一些临床观察和动物实验表明，口腔功能的缺陷降低了包括学习和记忆在内的脑功能的活动。然而，这一机制的细节还没有得到澄清。为了了解脑与口腔功能的关系，本课题对脑中的生物活性物质进行了研究，取得了以下结果：1)为了了解单胺类物质与三叉神经运动功能的关系，对超极化峰后电位和低电压激活的钙离子通道的特性进行了体外研究。发现5-羟色胺可增加三叉神经运动神经元的兴奋性。2)采用微透析法，在咀嚼c-…过程中，壳核中的多巴胺浓度显著增加。与静息期相比更多。损毁黑质纹状体多巴胺能通路的双侧6-羟基多巴胺可引起摄取行为中运动模式的改变。这些结果提示黑质纹状体多巴胺能通路在咀嚼过程中可能起一定的作用。3)实验动物在颞颌关节或腮腺致炎造成慢性疼痛时，记录到三叉神经脊束核尾侧核神经元的活动。结果表明，大鼠存在外周和中枢敏化，提示阿片类药物可能参与了这种敏化。4)利用仅给予软性食物限制咀嚼行为的实验动物，观察了后爪炎症时c-fos在背角的表达。用硬质食物和木棍激活咀嚼功能后，c-fos表达降低。这些结果提示，咀嚼作用的增强可能引起阿片类药物的分泌。较少

This project was to clarify the role of the nigrostriatal dopaminergic pathway in the sequential progress during mastication.Some clinical observations and animal experiments have been suggested that the deficencyt of the oral function decrease the activities of brain function inclulding learning and memory. However; the detail of this mechanisrn has not been clarified. In order to understand the relationship between brain and the oral function, we focused on the bioactive materials in brain, in this project.We obtained the findings in this study as follows ;1) To know the relationship between the monoamine and the activity trigeminal motor function properties of the hyperpolarizing spike afterpotential and the low-voltage activated Ca^<2+> channel were examined in vitro. It was found serotonine increased the excitability of the trigeminal motoneurons.2) By using the microdialysis method, the dopamine concectration in the putamen was found to increase significantly during mastication c … More ompared with resting period. And the bilateral 6-hydroxydopamine lesions of the nigrostriatal dopaminergic pathway induced the change of the movement pattern during intake behavior. These results suggested that the nigrostriatal dopaminergic pathway might play a role in the sequential progress during the mastication.3) When the experimental animals were induced chronic pain by making the inflammation in the temporomandibular joint or parotid gland, activities of neurons ln the spinal trigeminal nucleus caudaris were recorded. The data indicated the peripheral and central sensitization occurred, and suggested the opioid might be involved in this sensitization.4) Using the experimental animals in which masticatory behavior were restricted by giving them only soft food, c-fos expression, in the dorsal horn were examined when inflammation weas induced in hindpaw. C-fos expression was decreased when that experimental animal were activated the masticatory function with hard food and wood stick. These results suggested the possibility that is enhancement of mastication evoked the secretion of the opioid. Less