The study for co-relationship between the oral functions and the bioactive materials in brain

一些临床观察和动物实验表明，口腔功能障碍会降低包括学习和记忆在内的脑功能活动。然而，这一机制的细节尚未得到澄清。为了了解大脑和口腔功能之间的关系，我们在这个项目中重点研究了大脑中的生物活性物质。本研究结果如下：1)为了了解单胺与三叉神经运动功能活性的关系，我们在体外研究了超极化尖峰后电位和低压激活Ca2+通道的特性。研究发现血清素增加了三叉神经运动神经元的兴奋性。2)微透析法发现，咀嚼时壳核内多巴胺浓度较静息期明显升高。双侧黑质纹状体多巴胺能通路的6-羟多巴胺损伤引起进食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可能在咀嚼过程的序贯过程中起作用。3)当实验动物通过颞下颌关节或腮腺炎症诱导慢性疼痛时，记录三叉神经脊髓尾核神经元的活动。数据显示外周和中枢敏化发生，提示阿片类药物可能参与了这种敏化。4)实验动物仅给予软性食物限制咀嚼行为，观察后爪炎症诱导后背角c-fos的表达。实验动物用坚硬食物和木棒激活咀嚼功能后，C-fos表达降低。这些结果提示咀嚼增强可能诱发了阿片样物质的分泌。

Some clinical observations and animal experiments have been suggested that the deficencyt of the oral function decrease the activities of brain function including learning and memory. However, the detail of this mechanism 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 of trigeminal motor function, properties of the hyperpolarizing spike afterpotential and the low-voltage activated Ca2+ channel were examined in vitro. It was found serotonine increased the excitability of the trigeminal motoneurons.2) By using the microdialysis method, the dopamine concentration in the putamen was found to increase significantly during mastication compared 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 in 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.