The role of the basal ganglia in the bruxism and the development of the method for that estimation

磨牙症是如何发生的，大脑是如何参与磨牙症的，目前还不清楚。这个项目的目的是阐明基底神经节在磨牙症中的作用。为此，我们首先研究了磨牙症是否能够在实验中诱发，其次是基底节是如何参与口腔功能的。不幸的是，我们不能通过刺激基底节或造成基底节损伤来诱导磨牙症。关于咀嚼与基底节和黑质纹状体多巴胺能通路的关系，我们在本研究中获得了以下结果：1)根据颌骨运动的形式，兔的咀嚼序列可以分为三个阶段(阶段I，IIa，IIb)。研究发现，在第二阶段，电刺激基底节可以调节颌骨的运动。这一结果提示基底节可能参与了咀嚼过程中颌骨运动的改变。2)微透析法显示，咀嚼过程中壳核中的多巴胺浓度较静止期显著升高。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可能在咀嚼过程中起作用。在本研究中，我们展示了这些数据，提示基底节可能在口面部功能行为控制中发挥作用。我们希望我们的研究结果将对今后研究磨牙症的机制的实验有所帮助。

It is still unknown how the bruxism are occurred and how the brain is involved in the bruxism. The aim of this project was to clarify the role of the basal ganglia in the bruxism. For this purpose we first examined whether the bruxism was able to be evoked experimentally or not, and secondly how the basal ganglia was involved in the oral function. Unfortunately we could not induce the bruxism either by stimulation to the basal ganglia or by making the basal ganglia lesion. Concerning the relationship between the mastication and the basal ganglia and also the nigrostriatal dopaminergic pathway, we obtained the findings in this study as follows ;1) It has been known that the masticatory sequence in the rabbit can be divided into three stages (stage I, IIa, IIb) based on the form of the jaw movements. It is found that electrical stimulation to the basal ganglia during stage II modulated the jaw movements. This result suggested that the basal ganglia might be involved in the alteration of the jaw movements according to the progress of masticatory sequence.2) Using the microdialysis method, the dopamine concentration in the putamen increased 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.In this study, we showed the data, which suggested the basal ganglia might play a role in the control of orofacial fuctional behavior. We hope that our findings will be useful for the experiments studying the mechanism of the bruxism in the future.