A Comparative Study between Masticatory Muscular Activity and Regional Brain Function during Gum Chewing as Measured using a Whole-body Positron Emission Tomography

本研究旨在以局部能量代谢为指标，探讨咀嚼对全身活动的影响。本文用正电子发射断层扫描（PET）技术，以2 <15>O水为示踪剂，对9名正常志愿者进行了局部脑血流量（rCBF）的研究。另外4名受试者也用氟脱氧葡萄糖（FDG）测定咀嚼时咀嚼肌和舌肌的能量代谢<18>。结果：（1）在与咀嚼相关的肌肉活动中，FDG在舌内肌中的积聚最高。FDG-PET可在一次成像中显示咀嚼肌的相对劳动力。我们的结论是舌头在咀嚼中起着非常重要的作用。(2)全脑绝对rCBF增加15%，咀嚼胶基相比，休息条件。区域性增加在双侧初级感觉运动区最为明显。提示咀嚼对大脑有刺激作用，有利于心理健康。

The purpose of the study is to investigate the effects of mastication on whole-body activity using regional energy metabolism as a marker. A whole-body positron emission tomography (PET) was carried out using ^<15>O water as a tracer for regional cerebral blood flow (rCBF) in nine normal volunteers. The energy metabolism of masticatory and tongue muscles during chewing was also measured in another four subjects using ^<18>F-fluoro-D-deoxyglucose (FDG). Results : (1) Concerning muscular activity related to mastication, accumulation of FDG was the highest in the intrinsic tongue muscle. Heterogeneous regional uptake of FDG in the masticatory muscles, especially in the masseter muscles was found. FDG-PET could visualize relative workforce of the masticatory muscles at once. We conclude that the tongue plays a very important role in chewing. (2) The whole brain absolute rCBF increased 15% by gum-base chewing compared with the resting condition. Regional increases were most noted in the bilateral primary sensory-motor area. These results suggest that chewing and mastication stimulate brain and may be favorable for keeping our mental health.